All the ones I have ever played with go sort of pop.
Certainly there is no real loud noise and the blasters themselves tend to be brightly colored and do not resemble guns unless you are stretching definition of "look like" so far you could include leaf blowers, hair driers and Dewalt drills.
Right. We have a lot of Upnorth People in this area who are always going ballistic about car engines, woodpeckers, or even actual (legal) shooting nearby ... but Nerf guns go “plop.”
Egad. I’d be tempted to organize a Backlash in this situation.