It does sound like an intimidation issue and also does not sound very ethical in my opinion since it sounds like the agent brought the "expert" along.

Did the client request this "expert"? If so I wouldn't be as concerned about ethics, however, if the agent brought this expert along without the client's approval or informing the client about it then I would say that it is unethical if the "expert" is offering rebuttal or comments on your findings during the inspection. Without client being informed etc., it would appear that the "expert" is representing the agent's interests and not necessarily the buyer.

Besides, what are this "expert's" credentials? As we all know, being a contractor does not always make someone an expert, even in the field they work in (including HIs sometimes).

Was it the same agent each time that had the "expert" there?

Curious to say the least,

Eric