As a judge, you should really be watching what YOU are doing and not what your fellow judges are doing. The TC should be the one to observe this going on and then proctor the judge that this is an incorrect method. If this fails, then the rep should be involved. There were several instances at a recent Sams event where, as TC, I casually mentioned to all at the table the once a score is written, it should not be changes and another time, asked if anyone would like to fill out the comment cards. Both the question and comment had the desired effect without creating a major issue.
Was this correct? I don't really know but it had the desired results without embarrising a judge or causing an incident.