Prius Squeeky Rear Wheels

My GF is driving away in her 2005 Prius (75K miles) and I hear this squeek - it was a loud metal-on-metal noise. She drives it slowly from a stop and we determine that: (1) it is speed dependent, (2) it seems to go away once she gets above say 3 MPH, (3) it is louder on the right side, but might be coming from both rear wheels.

Then she tells me she’s been hearing this since having her tires rotated at the dealer two weeks ago!

Brakes or bearings? Any chance the dealer did something to cause this?

My vote would be brakes. Bearing noise wouldn’t subside at higher speeds

The car might have gone on a gravel road or through a car wash and had some gravel or other foreign matter lodged in the brake disc.