OldSteve:
You'll get away with it - the regulator's internal diode is rated at 15A peak, but it's not good practice and there's no real purpose.
Well that might be true for 78XX, LM3XX regulators.
But can you find those specs in a modern LDO regulator, like the xx1117.
Leo..
Edit.
Found it on the TI LM1117 datasheet.
Bottom of page 12.
10-20A for microseconds.
No continious current is mentioned.