|AJC1 / Foter.com / CC BY-SA|
So here is my 2c. When giving peer advice to authors considering a press please disclose anything that even looks like a conflict of interest, in the service of transparency and fairness. This means not only the obvious (being an owner or salaried staff member) but also being a commission-based staff member, friend of the owner, or even an author who has worked with the press long enough to develop friendships and emotional affinity to the company. Or if you feel you cannot provide objective feedback perhaps referred them to another author or just do not reply.
In the long run fostering unrealistic expectations is going to cause a press more trouble than letting the chips fall where they may.
*Edited to note the person in question categorically denies that they did this.