Dogs at HHN have become more common recently I think. specially because the actors like to see them and people take a lot of pics of the dogs in the zones. I know they are still service animals but on fb it kinda became a trend to take them to the zones and take pics. But also there were some actors that said that the job was really hard and that when they saw the dogs they felt a lot better that day, so in a way the dogs ended up being helpful to even the actors (just from judging what people were saying on FB)
I don't know how the dogs deal with the loud noises, but im sure they train them for stuff like that.