My Dad lives on a locked memory care unit and I like to take him out frequently. He has a girlfriend, also on the memory care unit, that I used to take out with him with her family's permission. That is, until she started refusing to return to the locked unit and then running down the street without minding traffic. I find this a dangerous situation so I don't take her along anymore, not to mention a legal grey area if she got hurt or killed on my watch. But frequently when I stop by to get my Dad (3-4x/wk) they are together and she gets upset when she can't come along. Sometimes I'm successful in coordinating 1) staff members who separate them prior to my visit 2) outings that include her family or 3) reaching my Dad on his cell phone prior to a visit to let him know his girlfriend isn't invited. However inevitably this does not always work out. Staff members have much higher priorities and I totally understand this or they separate them but still she manages to find me; the girlfriend's most devoted caregiver just moved 3000 miles away; my Dad forgets his phone or forgets how to work it. I've explained the situation to my Dad over and over but he still invites her along. So every visit is filled with tension. Last visit she followed me onto the elevator and nearly left the facility with me; I got the assistance of the receptionist but it was a close call. If anything ever happened to her I would be devastated and feel responsible.
Of course Dad isn't going to remember not to invite GF, even if he seemed to understand the explanation each time you provided it. He wouldn't be in the memory unit if his memory weren't impaired. And the GF also can't comprehend the situation, Neither one of them has bad intentions, but they are making your visits miserable. This is so sad.
Yes, staff is busy and overworked. But it is their responsibility to keep their locked unit secure. Alert them to the possibility of GF leaving the unit without authorization. Be firm that you are only taking your dad out. Staff should be grateful for this warning, even if it is an interruption for them. Believe me, if one of the residents in their care leaves the grounds unsupervised they'll have one huge interruption to deal with. You need to adjust your attitude about their role a little. They are not doing you a favor by separating Dad and GF when you come; you are doing them a favor by alerting them to a possible elopement.
They operate under the concept of providing a secure environment for residents. Dad's girl friend is entitled to that protection. It is not your responsibility to provide it. You tell the staff, and they deal with it.
The moment you walk into the facility, you go to a nurse/aid and ask them to get your dad. If he's with her, tell the nurse to make up something -- bathroom trip, change of clothes, whatever -- and bring him to you. If you can't do that, don't take him out that day.
If dad is blase' about your outings, then I'd simply stop taking him. Sometimes, we may find we do certain things because it makes US feel good -- not because it makes any difference to our loved one. There's nothing wrong with that at all, but, at the expense of another person? If dad doesn't really care one way or t'other? Don't take him out.