Update to P*ss on Toilet....
So, I waited and watched last night.
DH was all stressed and got on my case about nothing before dinner; I had to tell him "Really? Before dinner? Try starting over again." THEN YSD was just standing in the middle of the way, just standing there as usual so I said (for the second time this week - totally all passive aggressive but I'm done with it), "Oh, and I guess I'LL SET THE TABLE AGAIN."
Anyway after dinner DH goes to talk with her. I miss the convo, but know it lasted only about a minute, maybe a minute and a half. I heard her at one point start in with, "But I....." and "I don't....." and I heard DH cut her off each time. He KNOWS she did it because he cleaned it. He ended up telling her that the cleaning spray and paper towels are to be left on the counter and she was to use them each time she leaves p*ss on the toilet.
I thanked him later and reminded him he needs to check to make sure she's actually cleaning up....
AND THEN - she's also leaving early for BMs AGAIN for yet another 'event'. This had nothing to do with the above issue, it's been planned (as usual she doesn't tell DH until the night before she wants to go back). I say "yay" privately and tell DH I'm sorry that she's done it again.