My son (4.5) doesn't feel/notice a lot of sensations until they are extreme. This includes knowing he has to pee and knowing he is hungry. I can usually follow his cues and tell both of these before he can!
Still, we've only had three accidents. Ever. Chalk it up to him being part camel, I guess. Plus, there are multiple times per day when he has to try - not like a schedule or something, just that before we do XX, he has to try to potty. (I stress try, so he doesn't feel any pressure to actually do it. Yet most of the time he does have to go.) We all "try" before we leave the house, during adult swim at the pool, as part of bedtime routine, etc. Since we are always on the go, he gets a lot of chances. Of course at school they have potty breaks all together, too.
When he does finally tell me he has to go, I know he REALLY has to go. Last week was our first, uh, nature potty. He told me he had to go and instantly realized that tightening his car seat straps was 'squeezing his pee out' and he couldn't make it home or back to the pool restroom. My apologies to the curb.