Elderly relative has a device that's used for her emergency call button plugged in to the wall. It is vital that this remains plugged in. On a few occasions, this has been disconnected despite a note on it saying not to (and, I believe, some tape over it). The reasons for it being unplugged are unclear; no dementia but perhaps some mild forgetfulness. It may be the relative, cleaner or carer who had disconnected and not reconnected it.
Does anyone know of a device that can be used to lock a plug into the wall, but still allow it to be removed with a key or similar? I've looked at child proofing ones, but they appear insufficiently adult proof.