If you have a rail with a sign above it, place a minecart, get in the minecart, then exit, you will be teleported upwards. This probably isn't intended? It causes a lot of accidental minecart teleports.
To my understanding, there are not any designs in active use that use these hitboxless blocks for a minecart teleporter.
Checking if the block is one that has a hitbox before teleporting would greatly decrease the number of accidental minecart teleports.