The spell [Rescue] is going to be the new blight upon Eorzea

[Alkimi]

So many people are worried about this being abused... but rest assured it will be very infrequent that somebody does abuse it.

Ninjas have been able to troll parties with Shadewalker since 3.0 but you rarely see it. So yea, I don't see it being abused too much.
I can see it being used at organised endgame to minimize BLM movement, the healer effectively doing the mechanic for them with Rescue.

Although, the temptation to "rescue" the tank to the rest of the party half way through a Punishing Heat cast is very strong.