I have experienced wayback before when i was still participating on bounty campaigns which theres a campaign which do end up on being a scam and didnt paid off their bounty participants as well into its investors.This is also part of the risk when we do bounty hunting,its either we got being paid or not depending on the project we choose to advertise on.Knowing them if they are legit or not then this would really be hard.When it comes to tips then just do the basics on investigating or researching things.