it would be a good addition, although i think there should be more server side options than yes and no. there should maybe be a 'full' setting (warmup lap and yellow flags), 'warmup lap' (just the warmup lap), 'yellow flag' setting where the pace car comes out under certain incidents, and also the 'off' setting. I think on a warmup lap you get auto spec'ed for overtaking the pace car, and a drive through for overtaking under yellows.
surely not too hard to develop an on and off setting as a start due to the way the AI behaves now.