I will also not make names
If we talk of ccbill or big automated system who charge more then 10-15%, the shaving is unlikely, but when going into custom stuff, well...
I can tell that most programmers of custom adult affiliate systems can answer you about the shaving - as developers and not program owners.
I have let develop a few cam systems in the years and I been asked by several what shaving algorithm to implement!?
Well some called it cheat so looked like they figure it is a fraud, but some others called it "shave" which let me first think to my beard, then asking what he means, I figured it was hidden parameters to skip some sales for affiliates.
Now if programmers ask this to new customers it means they learned from old customers that this is an important feature of any affiliate program. When I said no need of any shave stuff, it looked like I surprised the developer, sorry to say, maybe I was the first did not needed (well I have just a dozen affiliate, I just buy traffic directly myself - and there I hit with bot traffic sold to me LOL).
I also learned those shave it is in trading traffic systems too, skimmed or whatever, and there was protraffic where the programmer actually stole the money for himself: "Protraffic.com was sabotaged by my ex-programmer. Our last statistics shows that he had stolen over $540,000.00".
Specifically for cam sites, I can tell that models reported me getting chargeback (in a cam site I will not tell) for customers they was in touch with via email whose customers said they did not chargebacked, so shave it happened also on model side, not only in affiliate side.
Specifically to cam sites, since 90% of sales is made by 5% of whale users, for a rev share deal it could be enough to make disappear the 1% of bigger customers to save 50% of payouts. So let's say you do $1000 a month with a cam site in rev share, if it keeps $1000 a month forever you not find it strange - but let one whale signup and he spend $5000 a month, you jump to 2k or 3k a month out of nowhere, for 1 only guy. Let this guy vanish for shaving algorithm, quick enough for you not to notice the 2k increase, and you'll keep doing the 1k a month and miss the unbelievabler extra 1-2k a month for 1 signup only.
A per signup deal drop instead would look suspect immediately, so if any shave is in place it may be less big to not be noticed, still a revshare thing in honest deal would be better, it is also not likely every site shave and to everyone and always, people are bad but not all so bad.
About adult biz people being more bad then others, look at madoff, lehman and other bankers, I think they shaved far more and from a good reputation position - adult biz starts with bad reputation by default like if you would expect a 10% shave as minimum by everyone, isn't it