I've have no experience with this, but I have seen discussions on this board where people report wheel bearing noise right after having tire work done (e.g. rotation).
One explanation I've seen, though I don't know how good it is, is that you might have a wheel bearing (or two) that are marginal and the properties of the changed tread pattern suddenly make it obvious.
One thing about bad wheel bearings is that you can't always tell they are bad when they are in the shop since you can really only check them with the wheels up off the ground - i.e. with no weight on them.
Of course, you do want to eliminate the new tires as the source of the noise. Some tires are just noisy. For a very quick gauge, get the exact make & model of the tires, go to Tire Rack's website, and read reviews about those tires. If the tires themselves tend to be noisy it should be obvious in those reviews.
A clear tip off that it is actually wheel bearings is if the sound very clearly changes when you turn (as you seem to imply). If you turn right and noise either appears or gets louder you're looking at a driver's side problem and vice versa. If it greatly lessens or disappears when you straighten out the wheels then bearings are very likely.
It also sounds like you want the shop to be "guilty" of something. If their goal was to rook you then I suspect they would have tried to add on work when doing the tires. At worst maybe they're just not all that thorough. If these tires came from a large chain operation then this wouldn't be surprising. If you don't trust them just get a second opinion.