added ability set unmountable entities

src/main/java/carpet/mixins/ServerPlayerEntity_scarpetEventMixin.java

@@ -1,5 +1,6 @@
 package carpet.mixins;
 
+import carpet.fakes.EntityInterface;
 import com.mojang.authlib.GameProfile;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.ItemStack;
@@ -53,4 +54,14 @@ public abstract class ServerPlayerEntity_scarpetEventMixin extends PlayerEntity
     {
         STATISTICS.onPlayerStatistic((ServerPlayerEntity) (Object)this, stat, amount);
     }
+
+    @Redirect(method = "method_14218", at = @At(
+            value = "INVOKE",
+            target = "Lnet/minecraft/server/network/ServerPlayerEntity;setSneaking(Z)V"
+    ))
+    private void setSneakingConditionally(ServerPlayerEntity serverPlayerEntity, boolean sneaking)
+    {
+        if (!((EntityInterface)serverPlayerEntity.getVehicle()).isPermanentVehicle()) // won't since that method makes sure its not null
+            serverPlayerEntity.setSneaking(sneaking);
+    }
 }