How long will your Signature Campaign last? Maybe you will evaluate its effectiveness and later there will be an opportunity to participate in a lower status.
If they wanted to get a lot of participants in the signature campaign, they wouldn't limit participation even for high rank users. Most likely there will be no changes.
They pay in Bitcoin and they have a limited Budget. If they will pay in tokens all Budget of signature bounty campaign will be divided among bounty participates. Always bounty with payment in Bitcoin are limited.