Like wiht any other appt, it is rude to be late.

2 hour window? oh brother! My would-love-to-say response would be, "I'm sorry .... do you honestly think I have NOTHING to do all day but wait for you to show up whenever you feel like it?" how utterly rude and inconsiderate. You're NOT walmart ... you're NOT open 24/7 with staffers behind the counter any time of day or night.
When I did consultations at my home and later in my shop, my confirming email flat out said, "If you are running late, give me a call. 15 minutes past the appt time, I consider you a no-show and I pack up and go home."
can you make a dr. appt and will he give you a 2 hour window to get there just whenever the hell you feel like it? I know mine won't! And he'll bill be for a missed office call and MAKE me reschedule!
"My pick up times are between 2 and 3. I have obligations after that and will be leaving at 3;15 and will be gone for the rest of the day. Just so you know, I do NOT give refunds for missed pickups."
Train your customers.
