Steve76,
Actually they do let pilots fly wearing hearing aids. I know of at least one pilot from your country (if you're from Canada as your profile says) who flies and wears 2 hearing aids as the result of a bad accident.
The only trouble I find with earplugs in hot, humid conditions is that they make the ears sweat even more and increase susceptibility to outer ear infections.
Wish my company issued us with Alpha helmets with ANR - that really would be an advance over heavy David Clarkes with poor noise attenuation.