Yep I’d have done exactly the same. There are some right miserable b*ggers at the pointy end of trains.
Your not wrong!
I went to London Paddington taking photo's of Class 43s for there 40th anniversary and was taking a sequence of 43002 on approach from the country end. When i reviewed the photo's a minute or two later, what did i discover but the nice GWR driver holding two fingers up to the windscreen, and it wasn't V for victory.
If i would have got to the buffer stop end before he had disappeared he would have got my two penneth.
I thought about posting the photo just to show him up, but then id be as bad and sad as him. Then just thought well if that's what makes his day, so be it, .
Anyway i can just airbrush that fool out.
I'm a VTWC driver and i let on to anyone. In a nice way. Other drivers from any TOC/FOC, platform staff, rail enthusiasts especially if i notice them taking photo's

, families & youngsters waving even passengers.
Certainly sound the horn when warranted especially to waving youngsters and those videoing if there signalling for it!