Thailand will only know about your travel to Thailand. The passport itself only contains information about your identity. Thailand will have no idea about other travel history. That's not the case for other countries, where there is a lot more sharing of passport data. Thailand I think is part of an ASEAN agreement to share data about ASEAN passport holders. The Migration 5 or 5 Eyes do more intrusive data sharing.
You don't always know the full details of these "first hand reports". A fair few are economical with the actualite, some are just made up for effect. Yes, there is much scare mongering.
Need one in Bangkok. She will have to travel to the VFS office for biometrics. All the agent is doing is essentially checking the paperwork is in order. Personally, I would let your girlfriend find and select an agent herself.
The ask:thailand community, consisting of multiple Q/A groups with over 100,000 members, powers this platform. It is not an official government resource. Our members actively contribute to this resource, and while we strive for accuracy, we cannot guarantee its complete reliability. Assistance to travelers is provided as a community service.