Being a regular, might mean that he thought he'd reviewed you in the past, and didn't want to make a new review because he has nothing new to add. It's possible to lose track of such things if you are busy.
Something else to consider, not everybody wants to be reviewed and are quite communicative of that, and some people won't write reviews if they know, or even suspect that the person they've seen doesn't like/want reviews. Especially if they are happy, and don't want to risk upsetting her because they did a review that was unwanted.
In my opinion there's nothing wrong with letting somebody know your preference on the matter in casual chit chat. Just let them know you are open to tasteful reviews. This is especially important because everybody is different. Everybody has different feelings and expectations in these circumstances and, unless I'm mistaken, we still haven't figured out how to mind read yet, so we have to talk openly and communicate well about the things we like/dislike. And do so without offense or insult in both directions.
