To be fair, paid signatures are even worse because these things are acting as a ground for a persistent corruption. There is seemingly no way to deal with this issue, unfortunately.
People are free to wear any signature of their choice, of course, but this action must lead to restriction of their electoral rights. Just like we have similar restrictions for those who are holding various positions in the public offices. Just for example, you can't be allowed to receive funds from the foreign power while working for the court. That would be simply a crazy loophole for corruption and fatal risk for integrity of the state. DT1 is actually no different from MP,  judge or court officer in that term.