How do the Family "Warp to" and "Warp them here" skills work?

It works like a VIP stone, I've been able to go from Henesys to Magatia. However there are some maps it doesn't work for, and of course you have to be on the same channel.

Ah, good, thanks. I'd swear I was on a normal map at the time, either a world tour or ludi, but it's been so long I've forgotten. I'll try it again whenever I have my laptop updated.