And above all, feels like a bad deal for the Republicans who take it: "Here, we'll give you TWO worthless votes in a safe-Blue state for your one vital vote in a swing state!" Oh sure, if you only want to "protest", but not actually catapult the orange shitgibbon into the Command Chair again, I get it. But still.

But anyway, as for the dubious principle: It's actually instutionalised in at least the Swedish parliament. They have this system where they keep track of who needs to be absent from a vote, and do a deal with parties on the other side of the aisle so one of those absents themselves too. Works out fine for practical reasons, I suppose: "OK, so Svensson from the Communists is back in his constituency today. That means Andersson from the Conservatives gets to run errands in Stockholm or whatever, in stead of having to show up for the vote". This is all conditional on their trust in this system, of course: If the vote was really important to the Communists, Svensson wouldn't travel to his constituency just then, if he didn't trust the Conservatives to absent Andersson or someone. But they do trust it, because they know next time t'll be Andersson or another Conservative who needs to go to their constituency, and therefore they too have an incentive to keep the system working.

Hmm, not only Sweden, it turns out: https://en.wikipedia.org/wiki/Pair_(parliamentary_convention)

So, yeah... If the legislators we elect with our votes can do it, why not the voters themselves too?

(Not that I have the faintest how they're proposing to build the trust required for it to work.)