Sorry but we all work by appointment, it's not book 'a half hour & stay as long you like' business. If you book half hour, more than likely we have other appointments booked arranged your time for leaving. I, for one, don't believe in allowing a client overstay & keeping the next client, who's probably turned up on time, waiting. Why should the next client be inconvenienced by waiting just because the previous client wanted to push his luck time wise?
Sandy x