The saying goes "call the obvious", and that is obvious.
Nobody calls a perfect game every time we step on the field, but you definitely want to get these. If the outside receiver flinched, or made a move that simulated starting the play there would have been a flag for FST, and I would treat this as the same. Did it have an effect on the play? Probably not, but again before or at the snap I think one needs to get these as obvious infractions.