I kept my rearview mirror on after getting my camper just so I have a place to hang my National Parks Access Pass from. Also, I still use it to check for boogies every now and then!I haven’t noticed the third brake light at night. The back cab windows on my truck are tinted so maybe that’s why I haven’t even noticed it?
Also, something I didn’t consider was the rear view mirror. Absolutely useless now, so I may remove it completely.