How do you know? Infractions aren't publicised. Junior wasn't banned for that post alone - his numerous infractions (not a ban by themselves) totted up to one.
Or maybe, given it's a very hot day, we've just played Fulham and / or we want to try something different that the playing conditions will be such that we don't want to justify charging punters to watch. 70 minute game? Rolling subs? Half with the youth team? All perfectly possible.