Tarmack
Rhetorical Porcupine
You need them to agree to it, otherwise you have no protection if they ask for it to be taken down. 1 of the options for reporting a video is "Infringes my rights > Invades my privacy" you show their face, they no longer have privacy. It's 1 thing if someone is accidentally in your video but if you're making them a part of it then you should let them know, don't be an areshole, it could potentially impact them in a negative way.
Quote a source please.