What qualifies as a disconcerting act is a judgement call, but chances are that if the linebacker steps up into the gap and claps his hands at the edge of the neutral zone, right next to an offensive lineman, that's intended to try to get the offense to false start -- which would be the definition of a disconcerting act.
It's doubtful you can be more creative than the average HS football player, so it depends on how much
YOU are willing to deal with creativity. The first time a player
(on either side of the line) gets "overly creative",
YOU can choose to ignore it, or advise him any similar efforts
will produce a flag, against him.
As for that first effort, if
YOU decide it crossed
YOUR line, flag it, but either way share your advice. It will make the rest of
THAT GAME a lot more pleasant (for everybody).