Signature is a lot like advertising. Different people participate in different signature campaigns. These are overseen by the project manager. There are many restrictions on signature such as scams, fraud, deceptions, etc. Signature campaigns are motivated by thoughts, intentions of help, opinions, etc.
Would someone be guilty of posting just to get paid ?
No, no one will be convicted but remember it is not the only way to earn. It is a platform for the overall concept and reality of Bitcoin. So, it should be posted with caution.