What if you wonder traded a Pokemon with your OT and ID.... then got it back?
Would it say "Welcome back, !" Or just the usual "Take good care of !"?
"It would say welcome back___!"
Source:Very Weird Experiment and Experience
It would say "Welcome back, !", the reason being is because it does this for regular link trade and even GTS so of course the programming won't be any different. It's programmed to say this whenever you recieve your Pokemon again.
Hopefully I Helped!