I noticed GR Teleport was able to add the option of not letting players TP when on the Cargo ship, and was wondering if you could do the same thing here.
The balloon would be nice too as the player bugs when using it on there as well. 

We have hard coded it to not allow TP from those two locations.

Can't you still /home?

I just updated it and it still allowed me to do so while on both.

If you are using 1.0.29 or 30, you should get an error message and not be teleported.  I just checked and even from a balloon on the ground I get the message.  This check is called for /town, /home, /tpr, and /tpa.