I believe the proper answer is that if you attempt to draw too much current from the output on the on-board +5vdc voltage regulator, you won't 'fry' the regulator but rather just cause it go into shutdown protection mode as part of it's internal over current and over temperature internal protection circuity. However applying too much input voltage to the regulator is certainly a possible method to 'fry' it, check the datasheet of the specific regulator to find out that maximum input voltage rating.
Lefty