I need some advice on Sunday mornings at church

My son has been doing great for a long time but every. Single. Sunday. He has to get a clothing change because he “missed” while using the potty.

He never has this issue anywhere else.

I can understand they don’t want to touch him to point him into the potty but he knows how to do it himself and I’ve told them that. Apparently they let him go all by himself even though we have told them not to so he always pees all over his pants while sitting on potty.

He won’t go right before church I’ve tried and he ALWAYS seems to have to go during church.

He’s 2.5

Thanks!!