You said:

"First off, the trade won't be even according to PB value because the high-PB value team has to give more than they get."

(I'm assuming here that you equate PB value with actual value so I'm reading this to say that the trade won't be even according to actual value because the high-PB team has to give more than they get. Making a trade even on PB value is meaningless).

Then you say:

"if I can't get a fair trade I'd much rather cut the guy than trade him for next to nothing. Maybe I can get him back in the FA, probably not, but I'd prefer that to getting ripped off."

Now which is it? Will you give up more than you get or will you cut the guy rather than trade him?

The whole thing boils down to what is "fair". In my opinion, from now till the FA draft a low PB team trading with a team likely over the PB cap should demand what would normally be considered an unfair trade and should NOT make any even trades (even on ACTUAL value) with them.