Thomas Shey
Legend
Did those rules questions actually exclude anyone from important parts of the survey?
I didn't take it myself--I'm probably a really unuseful respondent for a D&D questionnaire--but my understanding was that you sometimes couldn't get to the actual parts of the survey at all if you failed out on those questions.
If they did, then you might be right that it will result in over selecting. Otherwise, it's just a useful data point.
Personally, having taken the survey myself, I think getting information on what more casual players think about the product would be just as useful as from those with a lexicon like knowledge of the rules.
Certainly if you're interested in expanding your reach.