In that reverse robins au where Tim adopts Jason, I can just imagine Jason dressing up in Tim's old costume (probably Jason's idea tbh) and running around pretending to be Tim's ghost or whatever. Sure, up close they don't look the same, but from a distance, with Jason still having the build of a skinny street kid, I can totally see some of the bats mistaking the two at first.
Once Jay is more comfortable around Tim, yeah. I can see that happening 😭 or if we’re going with the assumption of the memorial case being a thing and the real suit not being available, Tim would have to deal with Jason insisting on accompanying him on patrol (just to make sure you don’t pull another head in duffle bags thing!) and, upon giving that suggestion a hard pass, find the kid following him around anyway in a cheap Walmart replica with customized gadgets.
Tim is stressed TM.
At least until he realizes how much it throws Bruce and Damian off their game, from then on out he utilizes that newfound advantage. 👁️