How many spammers do you think will pay? Not many, so your chances of receiving spam from from a paid relay are way less than from free ones.
Discussion
I see. So the higher the fee, the lower the spam?
Nostr Plebs has made roughly 1M sats over the past few days from spammers. Spammers will pay.
Sure, but much less. So it's easier for an admin to stay on top of.
Do you think is a solution to spamming? My feeling says no.