No, they are not going to say anything. People are allowed to meet up in the rooms.
Keep in mind that people do exaggerate when writing reviews. You say, "these reviews say..." - do you mean several of the reviews mention this; CM unlocking the door, coming in, opening the bathroom door and walking out? Or did one review mention that happening? Did they have the latch on? Did the CM just walk in using the key without announcing themselves? Did this happen to several people leaving reviews?
I've stayed at Disney resorts five times (values two of those times) since they started this policy; never once did a CM use the key and open the door. They always knock and announce themselves. Always. Most of the time they check the room during the day when we are in the parks.
They are not looking for people having dinner together in their room. If you are in the room and A CM knocks you can ask them to return later. As others had said, you can use the latch. If they just unlock the door and try to walk in unannounced that will stop them.