Well those will lead maybe into a ban in a short time is hard to manage one account at signature ,soo why people wanna to have 10 accounts at signatures to make their income bigger?Thats why some signature may fail since the income from the campaing is being paid to the cheaters,should be allowed only maybe 3 account by ip or user or computer otherwise we will see spam .
Many signature campaigns have restrictions to the number of accounts. It is open only one account for one user (one IP). Only for one or two more important is advertisement and efficiency.