many states have laws that prohibit that kind of thing. Public access to public restrooms....food establishments must provide reasonable access....that kind of thing.
As IBS and other diseases such as crohns become more well known to the public ...and as the baby boomers age there will be more and more laws stopping what you have experienced. You may want to look into what the laws are in your area and see how it applies.
To 78: I feel for you...I had to give up my fishing boat because I just couldn't accept going in a bucket and worrying about other boats coming by me on the open deck sitting.....I have had occasion to "go" in some unconventional places (always certain to clean upand not expose others to my issue). I do carry bags in the car and travel wipes along with TP in my glove compartment.
the worst for me was back in November when my wife was rushing me to ER with a major obstruction and yet I still had this massive urge to go....finally with no place to pull over to I had her stop along the side of the road....I dropped trou and sat on the plastic bag lined trash can that I was using to throw up in...and just went. Needless to say once I was admitted my poor wife had to go out wrap up the bag that had waste from both ends in it...and she even took it to the proper medical waste bin. Gosh I love my wife!!!!!