You might be on the ball but if there is a supposed problem, then either leave it be and see what happens or sort it out. It's doesn't only happen on hellopeter. I've had incidences of damage reports, which have been subsequent, but coincidentally was noticed , while we were onsite which then leaves you with 2 options ( whether or not the claim is valid ): 1. Ignore them and get bad mouthed throughout the industry ( and possibly not get paid ) or 2. Suck it up and take the knock to keep the client happy. In my line of work, I've found that taking a knock here and there, even for false claims, has actually improved business.
As for that user who is being silly by not contacting your support first... is your support information easy to find and readily available. Have you actually spoken to this client to find out why they are doing this instead of using the first point of contact? If they are such a problem then drop them.
False claims happen everywhere, you can choose to ignore it or not.