It is very hard work is the first thing to state,
Dont worry about over wetting the chairs it gets so hot in the auditorium they dry in double quick time,
You only quote on the cleaning the carpets NOT gum removal which is priced separately and they very rarely take it up because of the cost.
Never had any problems with payment always on time but most cinema budget on this type of thing is in house so the manager has to pay out his allocated budget, which they are loathe to do, thats why so many are in an awful state and stink of pewk and dirt.
Most are cleaned so badly because its done on the cheap and nothing much is achieved as a result, I have witnessed my self one cinema being cleaned by a 'team' of carpet cleaners. They had absolutely no idea what they were doing or how to operate the machinery, they just basically wet the carpet and left it, no actual cleaning was taking place. I pointed this out to the manager and told him to expect the carpet to shrink back with seams splitting (which it did) and to create a strong odour (which it did).
He thanked me for my input but was 'happy' with how it was being carried out (he meant the price). 10 days later we were back under the instruction of his managers as complaints about the smell had a serious effect on the sales of the concessions ,which is where they make their real money.
We cleaned and sanitised and had the carpet repaired which HQ paid for and would take out of the cinema budget the following year.
We have also carried out screen cleaning to great effect but never ever attempt this with out knowing what you are doing, almost immediately you can ruin a screen worth thousands of pounds.