No I don't write it that way. I think it's understood that you can't be held liable for someone else's work. City inspectors are not liable if your work is faulty or injure someone (except if negligent or "drive by inspecting"). The reality company usually gives a warranty with the house so they assume the repair liability. They are just looking for a professional to evaluate the existing wiring and bring any obvious problems to their attention.
Don't assume anything, if they understood you to say it is safe and something happens, they will try to accuse whoever they can. You may get out of it, but it will still inconvenience you at the very least. Write a report, detail what you have observed, note things like: at the time of installation GFCI protection likely was not required (for a specific outlet or area), current codes would require GFCI protection, and it would be a good idea for safety purposes to provide GFCI protection. Saying this does not in any wayt condemn the existing installation, but makes suggestion that it could use some improvement.
Whoever reads your report can look at it and see what the conditions are.
These areas are an immediate threat to injure someone or cause property damage:
xxxx, xxxxx,xxxxx
These areas could use some attention but maybe are not quite as much of an immediate threat:
xxxx, xxxx, xxxxx
These areas were not visually inspected and would require major expense or damage to building finishes to be able to visually see and evaluate them:
xxxx, xxxx, xxxxx.
If what is visible is deemed in pretty fair condition you can only assume that what is concealed is pretty fair. If there is a lot of questionable installation work in what is visible, then make a note that one can only assume the concealed items may have been installed by someone that was unqualified and the risk of some hazard being concealed is higher.