I am familiar with the school of thought that you need to run the engine hard to properly seat the rings. I'm pretty sure the engine is mostly broken in in that respect before it ever gets to the dealer. But there is also the transmission, differential, brakes, tires, etc. that need to be broken in correctly. Bedding the brakes correctly come to mind as something that seems to be neglected. I doubt this is ever done before you take delivery of the car. (You can look up how to do this on the internet for more info.) Plus, the engine has a different type of oil before the 1200 mile service so I feel that it is best to just go with what BMW says. It doesn't mean you have to completely baby it.
When I got the E46 M3 in '02 I tried to follow the break-in procedures but there was a time or two, sometime during the first few drives that I inadvertently went over 5500 rpm but not by much. This shouldn't hurt anything and BMW never brought it up during any servicing. I did run it pretty hard while still within the BMW recommended procedure and did not baby it. But I varied the speed (and throttle) almost religiously, never went over 100 mph, and floored it (again inadvertently) only once that I can think of. I gradually increased max rpm until 3000 miles. I never had a problem with the engine. It seemed to just get stronger and stronger the older it got.
The bad was that I was subject to the engine bearing recall. I had to go through engine break-in all over again
Hopefully, that sort of thing won't happen again.