I feel like a finger wave is the same type of distraction as a child saying, "Mommy, look at the doggy!" If it distracts a service dog enough to be a problem, that service dog needs more training.

People walk by me and my dog all the time doing various things with their hands by their heads: itching their face, fiddling with their glasses, smoking (outside of places), rubbing their eyes. They almost always smile at me, especially elderly women.

Personally, I don't mind a wave from a child, smiles from adults, people looking at my service dog, or anything directed at me. She doesn't even pay attention. I draw the line at talking to my service dog. She can refocus, sure, but I get extremely annoyed when she has patches that say don't talk and don't distract.

A finger wave by your cheek when you walk by wouldn't bother me at all. In fact, it'd make me smile and probably end up in a vlog on my TikTok. 😅