They are your guests, after all. Unless you are viewing them as the hired hands. As for lack of adequate facilities at the venue, perhaps looking for a better one would be a good idea, rather than putting up with an inferior dive as 'good enough for f*lk'. Or at least warning the artists beforehand of the shortcomings and inviting them to your home first. However, don't forget to deduct a percentage from their fee to cover the cost of soap and water used and food consumed.