A rental customer is safe, yes, but the poor sod who runs the company, who bought the aeroplane (and who is the Director, generally) is exposed to BIK.
What the Revenue really don't like is the common enough case where the business owner is also a private pilot. Again, this is not the law; the mere fact that the asset is available to the Director (or the employee) triggers the BIK liability. And of course many or most businesses are run by individuals who happen to have a personal interest in the activity - a bit mad otherwise to go into a business which you hate. But it makes a great deal of difference to how provocative the Revenue regards it. They don't like what to them looks like a "hobby business".
When I find out more I will post more details. In the meantime, back to my original Q: does anybody know what deal AOPA struck with the Revenue?