Sure you can sleaze 20000 easily, albeit a bit boringly. However I try to play mostly legit money earning and losing 20000 for a somewhat interesting, but not really great side mission doesn't seem great.
Some people reported that doing this mission "fixed" the issue with Johnny's items and other quest flagged items not being able to move to stash, sell or scrap. This didn't happen for me and maybe it's been fixed, because it seems like something not intended (you shouldn't be able to sell, scrap or store "quest" items.)
Since the mission leaves you nothing (except the "fun" of doing it) and instead you lose big, I returned to a previous save (having already experienced the "fun") and demanded a refund. Since I did start the mission, IDK if I still will have some problem with the Chippin In quest (which has also been reported), but I had no earlier save worth returning to.