A question to the Canadian legal minds out there.

Are searches of yourself and bags legal when entering a venue at a municipal park? In this case it is a ball tournament, which has beer gardens. Therefore the local Kinsman want to make sure you're not bringing in your own liquor and buying theirs. Fair enough, but the extensive slow search of everyone's ball bags and back packs seems like it contradicts the Canadian charter. Am I way off or AmIFreeToGo?