Disney does have a procedure. It isn't fun to clean up but I had my fair share of calls to custodial as a CM to help with a urine clean up. It would not be a protein spill/ code-v as those are vomit exclusive. My area called them yellow spills and a code B for the solid waste. Had a CP acquaintance quiet his second day because he had to go get poop out of the play area in Mission Space exit. From what I heard he went to his manager and said he didn't go to college to clean up someone else's poop.
It is totally disgusting, clean up procedure or not. She could have told the CM at the FP entrance that her little one desperately needed to pee and I'm positive they would have let her back in line when she got back.