Wow, it is very nice to have paid in btc by joining and participating on twitter campaign only.
What i know, the signature campaign is only the campaign that pays btc to their participants.
About bounty scam, i think the reward should be escrowed so it will give the guarantee of the payment and won't become scam campaign.
Yes, but if you go to a service place in this forum, you will see a twitter campaign that pays participants with BTC and the manager is also very trusted and many also hold signature campaigns with BTC paid which are always paid on time, meaning that such campaigns always have escrow in terms of the payment.