Does it really matter doesn't effect you and 'if' they are then I am sure they have there own reasons i.e. don't want people to look down on them and want to appear they have achieved to the level of everyone else.
Personally you could say this is evident on BOS with majority of people having marks over 90s but I think that is because of type of members BOS has and the others become to scared\reluctant to post after everyone is getting 99s and then complaining about it.
I personally haven't had anyone lie to me but then again they have no reason, not my place to pass judgement and even if they did I am sure they had there reasons and doesn’t effect me or my opinion of them.