[duxup]

I don't think it's a minefield.

Ignoring all the other details, if someone waves the magic wand and makes it legal you can use it, when someone waves the magic wand and it's not legal, then the agreement is just void at that point. There's no retroactive consequences.

[PaulDavisThe1st]

TFA notes that it may not have been declared legal. Rescinding a memo doesn't reverse existing case law; the meaning of said case law is subject to some disagreements (that the memo sought to clarify/remove).

[duxup]

Yeah I didn't want to go too far down the rabbit hole on the memo, just the most extreme case to demonstrate that if the law changes again, it's not a risk to the employer.