Does it really matter?
I'm not a big one on checking the oil hot, or cold, but (not remembering the exact numbers) it takes approx 250ml to top to bottom of the little window. This window is meant to show whether the bike needs topping up. If it is designed to give an approx 250 ml range, then why do we need to worry about how precise the levels are?
Personally I have a quick glance when its cold (if i remember), if it starts looking low, then I check it when its warmed up (10 miles commute). Never been a problem, not sure I can see why everyone is getting so het up about this.
My take on the whole It should be hot thing is more that the oil flows better when hot, so will settle quicker. BMW (or any bike manufacturer) don't know how you parked your bike, so have to assume that it could be on a big slope etc. If this is the case then you need to warm the stuff up before checking it, as it'll have all gone to one end of the engine. If the bike is sitting perfectly horizontal then I don't see what is wrong with checking it cold.
Anyhow why have I joined in this?????
Must get out and ride more....
TS