it wouldn't. spammers can do pow better than normal clients
Discussion
How about some initial sats payment that is automatically reimbursed if the relay operator does not decide to slash it? That would allow for much higher prepayment but come at low cost for honest users
I think that was the so Sphinx chat model. You give up sats to join a group and send messages and if the chat room owner decided it was spam they could keep the sats.
Then you'd trust the good intentions of the host.