It would depend upon how low is low. As the coolant expands under heat, the max pressure would be less than the system calls for as designated by the radiator cap. IIRC 18 PSI. The lower the pressure, the more chance of the coolant boiling. Once that happens, all hope is lost.
The idea behind the overflow bottle is that as the coolant expands and the system pressure reaches 18 PSI, the cap allows excess pressure to bleed off into the overflow tank. As the system cools and the pressure goes negative, the cap allows coolant to be drawn back into the radiator keeping the system full.
This assumes no leaks in the system and a good cap with a properly plumbed overflow.