My child I swear!!!!!!!!!

So I talked to the teacher with my son in the afternoon at the daycare since that seems to be when he has most of his accidents wetting his pants. We talked for awhile to try and figure out what would be best plan of action (this was a few weeks ago btw) and decided that she would send him to the bathroom every 30min or so and after snack, as well as before and after playground time since those 2 times seemed to be problem times for him. It seemed that he was just getting involved with playing and either didn't want to leave his toys because he was afraid the other children would take them or he just wasn't paying attention and waited too late. Teacher also sat down with him and told him that if he was playing with something and needed to go potty she would hold it for him so he wouldn't loose it, this is something she does for all children at that age because of their fear of loosing the toy they have and having accidents because of it (not done with the next age level up). So he was doing a lot better after all this for a few weeks maybe 1 accident a week which isn't too terrible for a 4yr old that didn't start to get potty trained until he was almost 3yrs old (so yes I am a little forgiving that the other children have an xtra yr of training on him).
Then comes this week. Either me, my husband, or both of us go to pick him up and all but one day this is what goes down: Get there and get a report of how good he has been all day, if my husband is there Ayden runs and jumps up in his arms and he checks him to see if he is dry (and he is)/if it is me I hug him and check him (and again always dry), stand there talking to teacher for a second finding out how his afternoon went, go get his stuff out of his folder,
next part goes one of these ways:
a)teacher says she checked him maybe 5-10min before but he probably should go to the bathroom before we leave, ayden starts crying that he already had an accident
b)we go to walk out the door and he starts crying that he needs to go change clothes because he is wet
c)we get to the car and go to put him in the seat and find out his pants are wet then and he has said nothing about wetting them

I am at my wits end with this child! I even bribed him to stay dry friday! He stayed dry on Thursday and was soooo proud of himself so I told him if he stayed dry on friday we would go do something special (we were going to go get his halloween costume, instead i had to go pick it for him because they only had 3 left in his size...had hubby discreetly ask him which one he'd like w/o him knowing what I was doing
) and still he was dry when I got there and right after teacher said he probably needed to go to the bathroom he started crying he had an accident. He would pick this week to pull that mess when we didn't have a washer and dryer because we had it on order and it took a week to get it here and then took few more days to hook up and get right parts. Odd thing is the one day he didn't do it only hubby picked him up, all the other days it's been just me or both of us there....maybe just coincidence or maybe something to it...IDK. I do know I'm going to go berserk if he doesn't knock it off!!!!!!! W have put him to bed early every night for it, taken away deserts, etc. The day he did well he got to come home and watch cartoons with hubby, eat dinner, get a few cookies after dinner, play in the tub (not allowed when he isn't good, it's in and out those days), pick his pj's, and go to bed at normal time...let him do stuff he doesn't normally get to do but likes to do. I'm at a loss but need it under control and fast before hubby leaves.