I got tricked!

Maybe she declined benefits. The pay difference is usually based on the cost of benefits that full time people get.

agreed. She probably gave up something else - like the confidence of her employer

This demonstrates one reason why you should never share salary information with anyone at work, ever. You accepted the drop in pay willingly enough until you knew what your friend was making. MYOB.

Your friend might not be telling you the whole truth.

They could be pursuing disciplinary action against her and just not telling her until they go through the appropriate channels.

I think your friend probably has a target on her at this point. I would feel frustrated, too, but I don't see Administration just shrugging it off if the pay is significant. There is something to this that she probably isn't telling you, IMHO. If you are otherwise happy with what you are doing and what you are making, I would not let it eat at you.

Just because she may seem slick enough to get paid more, doesn't mean you are being screwed. You are being honest. They realized they messed up the paperwork and were paying you too much. At least they didn't ask for it back! I know a RT who had legal problems a few years ago for such a thing. Your friend will have some price to pay, whether it is benefits, legal issues, scheduling issues, or god knows what. And maybe it worked out with night shift differential, although that seems unlikely unless it is a large differential. Word will somehow get around. And when it does, it will be "well she can work some weekends because she's getting paid like a PRN" and holidays will also have some drama. There will be resentment.

You, on the other hand, have skipped all this crap and are working. So be happy.

Yes you got tricked. You shouldn't have signed this without thinking about what you were really doing. HR looks out for the interest of the employer, not you, no matter how they try to spin it. Don't be too eager to please your employer especially when they can't do anything about it unless you voluntarily sign a paper. You had the ball in your court and you just gave it up.

I have a friend who did the same as your friend. He is getting paid PRN pay as a full time employee and has been for years now. Granted I'm not sure what, if any, benefits he has. Still, I wouldn't hesitate for a second to do something like this if the opportunity presented itself. Trust me, your employer will drop you like a hot potato or take advantage of you whenever it fits their interests. Who do you want to live your life for? Yourself or a company?

Oh, and I bet your friend isn't going anywhere..except the bank laughing all the way.