Good question. First, when a subcontractor threatens an owner with a mechanics lien claim, it's generally a good idea to discuss the issue with that subcontractor's customer (i.e. the contractor or sub who hired the person threatening to file a lien) to see where the dispute has come from. That might be helpful in getting a baseline for who's owed what and whether a lien claim might be filed. And, if that subcontractor threatening a lien has truly not been paid, owners are generally in pretty good position to make sure that payment is ultimately made.
Further, it might be helpful to take a look at who has submitted lien waivers, if waivers were collected on the job. If a potential Georgia lien claimant has waived their lien rights and if more than 60 days have passed from when the rights were waived, that claimant will generally not be entitled to file a mechanics lien.
Further yet, 44-14-361.2 of the Georgia lien statute provides an option for blocking potential lien claims from sub-tier claimants (those hired by someone other than the owner) where full payment is made to the contractor. If an owner receives a written and sworn affidavit from their contractor that all payments have been made, and if no claims for payment are made before that time, then claimants on the project will generally not be entitled to file a mechanics lien on the project (unless the claimant had previously filed a Preliminary Notice of Lien Rights in the property record).
Finally, note that it's hard to prevent a lien claimant from filing their lien in the first place, but threatening to take action of your own could help persuade a would-be claimant from filing a lien when their claim is bogus. For one, Georgia owners can always bond off a filed lien. That won't make the lien claim disappear, but a claimant will have to work harder to obtain payment if the lien is bonded off rather than paid. Granted, for claimants with valid claims, threats of bonding off a lien might not be bad news. Another option might be to inform the claimant that their claim would be exaggerated or fraudulent and to inform them of what counter-actions will be taken if a lien is ultimately filed.