The problem with doing that is when the attendant will actually walk back to the car with you and give it their own "smell test" and you stand there like Barney Fife shuffling your feet back and forth. That happened to me a couple of times but I persevered and told the attendant that my sense of smell is pretty accurate and unless they were prepared to "upgrade" me to another car ( which would have been a luxury car ) then they needed to notate on the paperwork that I was taking the rental under protest because of the smell and they were only too happy to do that. Sometimes it worked and I would get a nice luxury car upgrade or I'd get the original car with a "pass" and I'd smoke cigars the entire time I had it. Is this ethical? Nah but while I drove off in the car I said a few Hail Marys and I felt better about the whole thing. Things us cigar smokers will do to deal with our hobby!