I think I would want something to dampen the sound at least for the boy if I were you -- I would try for bjl too if you can convince her to not mess with it. We used to use ear plugs on G when we took her to Sounders games. She wouldn't stand them by the end of last season and pulled them out of her ears but now that she's old enough to semi-reason with, we'll try again with her. They're a neon orange kind for kids and you smoosh them over their ears, not inside (so kinda like pinching your ears closed with your fingers). You can get those at pretty much any drug store, I think. I've also seen kids with noise-blocking headphones but I think they're more expensive and wouldn't know where to buy them.
Thank tou 7costanza and @lauralynne, but I think I finally convinced my husband that it was a bad idea! I told him to go on his own but I think I pointed out the negatives enough that he may not go himself!! (Traffic or bus rides several hours prior).