Trading waiver priorty

Is it a dirty move to trade waiver priority?

Super heated debate in our league would appreciate some feed back.

How is that even possible? Grab someone the person wants and then trade for something or?

Yep, the top guy came to one of the bottom guys and asked to trade his waiver priority.

If he gets something in return I have absolutely no problem with it. If it’s just, hey, lemme use your waiver pick you don’t need it… Then it’s collusion. So essentially they are just literally switching waiver picks?