If you leave it in warm weather for any more than 2-3 days, the toilet will stink during every flush - this is because, unlike a vacuum system, the Challenger toilet flushes with the same stuff that has been deposited in the tank. No matter how much "blue loo" you use, you can't stop the stink!
I never passed up to opportunity to dump the lav system in the Challenger at the end of the day.