It's difficult to believe that hoses could expand enough to accomodate about 15% more coolant. I'm curious, when people had the low coolant message, was there any coolant visible in the reservoir? If some was visible, I wouldn't have a problem driving it to the dealer for a top-up. If not visible, then you really have no clue how low it is and I would be hesitant to risk driving it.
2013 x35i (Space Gray, MSport, CW/CWII, DHP, Premium, Premium Sound, Technology, BMW-Apps)
Retired:'09 C300 4Matic, '09 GTI, '06 750i, '05 C55, '04 R32, '03 M5, '02 GTI, 01 M5, '00 M-Coupe, '00 540i/6, '99 M3 Coupe, '98 M3 Coupe, '96 328i, ..., '86 4000CS Quattro, ... too many to list