Wouldn't get very far. The first one will pull out when they see you've broken contract terms by posting something they didn't give approval for. Or worse, defrauded them.
It's an amusing fantasy, sure, but alas, that's as far as it goes.
Unless... the point is not so much the legit ones that actually care, but the ones that don't, that don't even notice that you literally have "shill" in the name.
A good argument against that is, "any news is good news", and you're just encouraging bad behavior (indeed actively participating in it).
There's also possible fallout from your existing advertisers, who may drop when they see how you're treating others. This seems like a lower risk, given the low-key ads you accept right now.
Of course anything done on your own, no money, no contract, that's 100% fair game. Want to shit on whoever's spamming you this week? Go all in!
Tim