Pottytrained 2.5yo refuses to ever "try" before leaving house

We have a pottytrained 2.5yo who in recent weeks has decided to put off going to the bathroom as long as possible. This has meant a lot of messes because once she gets to the bathroom, as she often doesn't have time to take her undies and pants down anymore. She cleans them up, we move on.But this resistance to the potty has also moved into avoiding taking "try" potty breaks before we leave for the park, store, etc. We've tried just leaving her behind with the other parent if she doesn't take it, physically carrying her to the toilet, 2 minute warnings, etc. Since a lot of parks here don't have reliable bathrooms it's really important she take one before leaving (she also refuses to pee under a tree when the situation has arisen) and we just can't get her to without a huge tantrum each time at the least. She understands she's missing going somewhere (which further upsets her) but doesn't connect it with her actions. Looking for other suggestions or just reassurances it was a hopefully short phase! via /r/Parenting http://ift.tt/2vckjPg