For ease of answering the question that was asked, I went ahead and quoted Shawn. Looking at the 2nd and 4th paragraphs(?), I have been to a lot, and I do mean a lot of shows, many of them IPMS shows. I have judged many shows also, my club’s shows and I have been asked to help judge at IPMS shows. Fact is, I’ve already been asked to help judge at this coming Saturday’s IPMS show in Pittsburg, TriCon. Not one single solitary time have I ever seen or heard of in the judges meetings prior to the actual judging, “be on the lookout for hood props!” Honestly, shows are notoriously poorly lit and if you just prop open the hood the judges aren’t going to get that great of a view of the engine bay. I would hazard a guess that it is easier and more advantageous to just remove the hood and lay it beside the car.
You asked what we have typically ran into and I answered your question. I hope this helps.