My post was written based on personal experience so I fail to see why it was deemed 'shit advice'.
Having bought many fairly new cars from dealers without driving them or problems previously I bought a two year Golf from a VW dealer.
Sadly it turned out to be a pile of abused shite so I sought advice and was informed that because I'd bought from a dealer I had 30 days or 1,000 miles to return it for a full refund for no reason other than I didn't want it.
My thoughts on reading of the failed switch problem and that the suppling dealer hadn't yet agreed it would be covered by guarantee was to suggest returning the bike for a refund.
If the bike was returned for a refund the dealer would need to repair and resell it so I would bet on them agreeing to repair it so as not to have it back.
Shit advice? I don't think so.
I agree with everything you said above, I can't argue with it in principal nor would I want to. BUT, it seems a little drastic to be weighing up the option of returning it before giving the dealer ample chance to rectify the issue. BMW's are (as far as I'm aware) notorious in recent years for switchgear issues and I suspect the dealer refused to state it WOULD be a warranty job purely in case they got the bike in to find he'd been dicking around with stuff and actually caused the problem himself. I'm just assuming.
Obviously if the dealer says it's not covered then the route of rejecting it would be totally acceptable (in my humble opinion). I've found so far the dealer network to be quite good when it comes to warranty work.