Hi Steve,
Do they know that, to do that, they only need one additional click in the "Select all" before starting to click in the items to exclude?
If we add the ability to "not include", I believe you want to keep the "include" so, we still will need an additional click or selection to choose include/not , or am I missing some detail?
Obviously that I'm not trying to block the suggestion, and apologize if this was already discussed with your customer.
Have a nice week