Couple things:
a) The text for keyring teleporting should warn you that it will use one of your 2-3 energy map teleports (if you have the appropriate skill) or 5 token map teleports per day.
b) After you have used all your energy map teleports (and presumably the same for tokens), the option to TP via energy isn't greyed out when you go by keyring, like it is when you use the map to TP.
c) If you click on this anyway and try to use an extra map teleport, it doesn't let you, but it does notify the house owner that you have entered, even though you are still stuck in place and have not really teleported into their house.