That's true but no PSU can take unlimited amps on the 5V rail. But I guess a quality PSU should shut down before a melt down happens.
it is/was a 800W odin modular psu. it was pulling about 17A (max25A 5v) from the rail in question that starting overheating i think the fan got stuck or something. i have it outside of the pc powering 3 av16 at the moment and no problems, bad connection maybe....