Most proposals are limited to whitelisted addresses.
Most Polymarkets are linked to a Managed Optimistic Oracle Version 2 (MOOV2) request. MOOV2 requests are whitelist-only.
The proposer whitelist can be found at the bottom of each MOOV2 request in the UMA Oraclearrow-up-right.
The MOOV2 proposer whitelist was created to reduce the number of disputes caused by first-time proposers. Read more herearrow-up-right.