diff --git a/src/main/kotlin/eu/fosil/okupamicoche/cli/CommandParser.kt b/src/main/kotlin/eu/fosil/okupamicoche/cli/CommandParser.kt
index 6f56406..f6e1b14 100644
--- a/src/main/kotlin/eu/fosil/okupamicoche/cli/CommandParser.kt
+++ b/src/main/kotlin/eu/fosil/okupamicoche/cli/CommandParser.kt
@@ -1,5 +1,6 @@
 package eu.fosil.okupamicoche.cli
 
+import eu.fosil.okupamicoche.matrix.MatrixApiClient
 import eu.fosil.okupamicoche.matrix.matrixApiClient
 import eu.fosil.okupamicoche.model.TravelOptions
 import eu.fosil.okupamicoche.usecase.Usecase
@@ -9,7 +10,6 @@ import eu.fosil.okupamicoche.usecase.travel.leaveTravel
 import mu.KotlinLogging
 import net.folivo.trixnity.core.model.RoomId
 import net.folivo.trixnity.core.model.UserId
-import net.folivo.trixnity.core.model.events.m.room.RoomMessageEventContent
 import java.time.Instant
 import java.time.ZoneId
 import java.time.format.DateTimeFormatter
@@ -49,9 +49,10 @@ object CommandParser {
         } catch (e: Exception) {
             logger.error { "Exception captured: $e" }
             e.printStackTrace()
-            matrixApiClient?.rooms?.sendMessageEvent(
+            MatrixApiClient.sendErrorTextMessage(
                 room,
-                RoomMessageEventContent.TextMessageEventContent("Error executing command: $e")
+                "Error executing command: $e",
+                "Error executing command: <code>$e<code>"
             )
         }
     }
diff --git a/src/main/kotlin/eu/fosil/okupamicoche/matrix/matrixApiClient.kt b/src/main/kotlin/eu/fosil/okupamicoche/matrix/matrixApiClient.kt
index c24abbd..11ce3d7 100644
--- a/src/main/kotlin/eu/fosil/okupamicoche/matrix/matrixApiClient.kt
+++ b/src/main/kotlin/eu/fosil/okupamicoche/matrix/matrixApiClient.kt
@@ -12,6 +12,7 @@ import net.folivo.trixnity.clientserverapi.model.rooms.DirectoryVisibility
 import net.folivo.trixnity.core.model.RoomAliasId
 import net.folivo.trixnity.core.model.RoomId
 import net.folivo.trixnity.core.model.UserId
+import net.folivo.trixnity.core.model.events.m.room.RoomMessageEventContent
 import net.folivo.trixnity.core.serialization.createEventContentSerializerMappings
 
 private val logger = KotlinLogging.logger {}
@@ -55,6 +56,24 @@ object MatrixApiClient {
             userId.full.substring(1) // Synapse throws 403 if stateKey starts with '@'
         )?.getOrNull()?.membership
 
+    suspend fun sendErrorTextMessage(
+        roomId: RoomId,
+        body: String,
+        formattedBody: String? = null
+    ) {
+        requireNotNull(matrixApiClient)
+
+        val formattedBodyWithWarningIcon = "⚠️" + (formattedBody ?: body)
+        matrixApiClient.rooms.sendMessageEvent(
+            roomId,
+            RoomMessageEventContent.TextMessageEventContent(
+                body = body,
+                format = "org.matrix.custom.html",
+                formattedBody = formattedBodyWithWarningIcon
+            )
+        )
+    }
+
     private suspend fun createMainRoomIfNeeded(): RoomId? {
         requireNotNull(config)
         requireNotNull(matrixApiClient)
diff --git a/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/joinTravel.kt b/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/joinTravel.kt
index 94ba545..02a2307 100644
--- a/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/joinTravel.kt
+++ b/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/joinTravel.kt
@@ -19,25 +19,16 @@ suspend fun Usecase.joinTravel(
     val membershipState = MatrixApiClient.getTravelMembership(roomId, userId)
 
     if (!isTravel) {
-        sendErrorTextMessage(roomId, "There is no travel.")
+        MatrixApiClient.sendErrorTextMessage(roomId, "There is no travel.")
     } else if (isDriver) {
-        sendErrorTextMessage(roomId, "You are the driver, you don't need to join.")
+        MatrixApiClient.sendErrorTextMessage(roomId, "You are the driver, you don't need to join.")
     } else if (membershipState == Membership.JOIN.value) {
-        sendErrorTextMessage(roomId, "You were already joined.")
+        MatrixApiClient.sendErrorTextMessage(roomId, "You were already joined.")
     } else {
         sendJoinedMessageEvents(roomId, userId)
     }
 }
 
-private suspend fun sendErrorTextMessage(roomId: RoomId, messageBody: String) {
-    requireNotNull(matrixApiClient)
-
-    matrixApiClient.rooms.sendMessageEvent(
-        roomId,
-        RoomMessageEventContent.TextMessageEventContent(messageBody)
-    )
-}
-
 private suspend fun sendJoinedMessageEvents(
     roomId: RoomId,
     userId: UserId
diff --git a/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/leaveTravel.kt b/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/leaveTravel.kt
index dcc7417..b04dc18 100644
--- a/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/leaveTravel.kt
+++ b/src/main/kotlin/eu/fosil/okupamicoche/usecase/travel/leaveTravel.kt
@@ -19,27 +19,22 @@ suspend fun Usecase.leaveTravel(
     val membershipState = MatrixApiClient.getTravelMembership(roomId, userId)
 
     if (!isTravel) {
-        sendErrorTextMessage(roomId, "There is no travel.")
+        MatrixApiClient.sendErrorTextMessage(roomId, "There is no travel.")
     } else if (isDriver) {
-        sendErrorTextMessage(roomId, "You are the driver, you cannot leave. You can cancel the travel if you want.")
+        MatrixApiClient.sendErrorTextMessage(
+            roomId,
+            "You are the driver, you cannot leave. You can cancel the travel sending '!cancel' if you want.",
+            "You are the driver, you cannot leave. You can cancel the travel sending <code>!cancel</code> if you want."
+        )
     } else if (membershipState != Membership.JOIN.value) {
-        sendErrorTextMessage(roomId, "You are not joined. state=$membershipState")
+        MatrixApiClient.sendErrorTextMessage(roomId, "You are not joined.")
     } else if (membershipState == Membership.LEAVE.value) {
-        sendErrorTextMessage(roomId, "You already left.")
+        MatrixApiClient.sendErrorTextMessage(roomId, "You already left.")
     } else {
         sendLeftMessageEvents(roomId, userId)
     }
 }
 
-private suspend fun sendErrorTextMessage(roomId: RoomId, messageBody: String) {
-    requireNotNull(matrixApiClient)
-
-    matrixApiClient.rooms.sendMessageEvent(
-        roomId,
-        RoomMessageEventContent.TextMessageEventContent(messageBody)
-    )
-}
-
 private suspend fun sendLeftMessageEvents(
     roomId: RoomId,
     userId: UserId