If this done at an appropriate time, I have no problem with it - i.e. immediately after the end of the rally. However, if the team is late with it and after I've beckoned for serve by the other team, then IMO I have an issue with it.
I've only seen this once. It was 2 years ago in a GJV match, and the team did it after every point. During the first set, I slowed down to allow it so as not to disrupt the other team's server. However during the set break, I called the coach over and had a talk with her - do it but not after the call for service. Her answer was "well, we've been doing it all season". DUH!!
Y.U.D.