I don't know. If you knew the cap was there and you knew they would slow you down, to me it's like saying the State police are doing bait and switch because all of a sudden they started enforcing a speed limit of 55 in an area you have always driven 90 in.

They are providing the service you agreed to. Over 5 gb, you get much slower. If the agreement didn't say how much slower, and you didn't ask, well that pretty much leaves it up to them.

Not really sure how it is bait and switch.