This 3 strike rule seems a bit childish,If I get a persistent problem with a customer I just drop them,I can't be bothered with the hassle and I work for myself and chose who I want to work for,I been to price up jobs and then walked away because of their attitude,I think its better to have 10 customers that pay regularly than 15 where you get loads of hassle.Told one X-customer that I can sit at home and not get paid.I don't think a customer would use the 3 strike rule if they had a problem with you it cuts both ways as far as i see it.