I used to have a 1 gallon pail for my guest that said "Ladies Room" until one day a lady said to me....that's just disgusting.
The most interesting thing I have seen was another lady who when asked what to do simply told me not to worry, she had been fishing for over 40 years and this was not a problem. Later in the day she asked me to excuse her for a minute and reached into her pocket and pulled out a 1 gallon zip lock bag, did her business, poured it out rinsed and folded and put back into her pocket