Let me get this straight: you feel the hotel should have someone sit at the parking lot exit 24x7 just in case someone has lost their parking ticket? This isn't a luxury hotel, but even if it was, I doubt that you'd see that kind of staffing outside of a developing nation.

If the OP went back to the desk after there was no response and had been treated rudely, it would be an entirely different situation than what he says he did do. His actions were identical to what someone who parked for several days and was trying to skip out of the majority of the payment would do. They appear, on the surface, suspicious.

I am not saying that the OP did this intentionally, nor am I saying that "Juan" is a candidate for Hyatt employee of the year, but certainly this is a different situation from the one you described.