I have had to use the guarantee, generally when room service didn't come through (one time after a reminder).

On the same note, at check-in I generally hit the agent with a few things: Premium Pound (want a receipt showing value), call in a crib or rollaway, request an upgrade or specific room etc. Many times when I hit them with that (especially the pp) they forget the card. In those cases I remind them, and if I forget too, just approach the desk and ask the agent for the card. (yes I could wait and get the $$, but have always felt like if I had a pleasant check in experience, I can give them the opportunity).

One other time, I had a rotten check-in from an agent with an attitiude, she forgot the card, and found the front desk manager at this property had the same attitude. Had to use the platinum line to collect the $$, and never returned.

As I said earlier, if I wanted to, I could definitely collect $$$. Simply break the usual check in pattern with a PP requesting a receipt, or cash a check, etc. Not my cup of tea.

If you go in pissed, with an attitude, you'll get what you are expecting...