Spouse going to special pop pt

So a friend of mine in a different unit just called me up telling me that he just found out that one of his Soldiers who is in special pop pt is bringing his spouse. Now the spouse isn't in formation but she is standing on the side conducting the pt that is being done. Now I'm all for spouses getting in shape but I feel like this Soldier's wife should not be attending pt during the duty day with the Soldier. I feel like it is unprofessional and other Soldiers could take issue with it. My question, is there a regulation or liability issue that says your spouse can't accompany you to pt during the duty day? I tried to look it up but I have come across absolutely nothing on this. Any help would be appreciated.