from now on, the campaign manager, the escrow provider as well as the owner of that site should start storing funds in a multi-sig wallet where if anyone goes AWOL, two others can simply approve themselves and send the funds out to the participants. Although it's a tedious process, it'll possibly be the perfect process for running a secure signature campaign.
Is there any kind of service offering automated 2-of-3 multisig? That seems like the obvious way forward here. The company wanting to pay for forum signatures creates a campaign on the site, the forum users each sign up for that campaign. Everyone provides an address. The site makes a 2-of-3 address for each campaign participant, holds funds in escrow, but can't steal them.
If so, why don't people use it?
And if not, I'd be interested in setting something like that up. It could charge a small fee, and give the fees to the people who lost out to this master-p scam.
It would feel a bit icky contributing to forum signature spam, but I don't think that's ever going away anyway.
