I think the point the cma was making is that this trick doesn't involve making changes to (formal) stock-sale plans. The formal plan is to sell regularly, and that remains unchanged, you just cancel it by hand habitually, except when you don't.

I am no lawyer, so I don't know if this is really allowed. My gut instinct is (a) no, it is not allowed and (b) there will always be some more subtle version of the tactic that is allowed.