Spare keys?

I have a new '06 MCS. I have the standard complement of two full 
remote-key-fob keys plus the plastic "spare" key.

1) rumor has it that the spare key will only work a certain number of
times 
before ??? What? the car locks up? The spare doesn't work anymore --  
permanently? until you use the real key again? what?

2) The dealer implies that there is no middle cost key - e.g. a real metal

key (w/o remote) but better than the "spare". Is this true? I would really

like a real, metal key, with RFID, but not the remote control bits, so
that 
I can safely take it in my bathing suit into the ocean for a swim, etc...
I 
thought there was a "valet key" available that was what I wanted, but I 
don't remember where I heard this...

Does anyone have a source for "real" keys that don't have the remote
control 
built in?