If they have a skippers meeting, possibly ask someone to point out all the marks of the course during the skippers meeting.

Since you mentioned that you are new to the club, you might want to leave it at that, or you might want to take him aside and tell him that people are watching, or depending on how much you want to embaress the fellow, you might want to then look directly at him and ask him if he can see the mark locations without his glasses.

Also, enlist the help of one of the other skippers that has been around a while to "keep an eye" on the offender.

Because you are "Norman New guy" there is a need to tread lightly, but if this has been tolerated, there are others that are not happy about it, and will jump at the chance to put an end to it.

Of course there is the possibility that he just made an honest mistake, and "getting caught" will assure it will not happen again.