I imagine that will be up to them and is yet to be determined. They will choose the rules of engagement for the SMT. It is likely they will have some requirement for holding of the token to stop spam but will delegate that to new accounts that are verified with a phone number or attached to a unique phone ID or something similar. SMTs are still under development so there is some uncertainty as to how it will all work. You can see the whitepaper here https://smt.steem.com/