I think it's important for both parties to respect each other.
For an Escort Time is Money. Having potential clients mess them about by not confirming when they will arrive or just not showing up without cancelling the appointment must be incredibly frustrating, making it extremely difficult for them to plan their day and earn a living. A client should have consideration for the escort by confirming they will be there at the agreed time or cancelling the appointment in adequate time.
On the other hand Escorts should respect the clients by letting them know if they are running late or whether unforeseen issues mean they will have to cancel the appointment at short notice. A lot of the N/A reviews seem to be as a result of client frustration when they arrive at the appointed time only to be unable to contact the escort they had booked with.
I really look forward to my appointments and would hate for anything to happen to ruin my plans so I always send the confirmation text 30 minutes beforehand. Luckily I've never had any issues so far (Touch Wood). But if for some reason I had to cancel the appointment then I would try to do so in plenty of time for the escort to make alternative bookings.
A little respect goes a long way.