You find out when they deactivate you. We don't have a list. We just know that sometimes it happens.
You need to think of your scheduler as being like your direct supervisor if you were employed. They decide who gets the jobs, so why wouldn't they be able to deactivate you? It probably depends on if the scheduling task is shared among a team, or if one person controls the whole territory.
They need their business to run smoothly. If a scheduler is having problems with a shopper, it's easier (they think) to find another shopper. Sometimes they're wrong.
I had a scheduler decline to pay me $5 for a failed shop (oil change shop; they were out of oil) and said I could redo it for the same fee. When I told her I wouldn't do it unless she paid me for the travel for the first attempt she replied, "There are plenty of other shoppers who will do it." At the end of the month, I loaned a friend of mine $40 to front the expense so she could do the shop. So indirectly, she still didn't get the shop done without me. They can be so arrogant sometimes. I think most of us know our market better than the scheduler. I knew there was nobody else in this small town to do that shop.
After she struggles to get that shop done by someone else, she'll regret being such a @#$%& about it. But you'll have moved on to something else. If she swallows crow and calls you about it next month, tell her the price just doubled.
Time to build a bigger bridge.