Another thing to think about:

Besides your comportment while backcounting, your jumping in mid-shoe and then jumping out may have annoyed another player at the table who subsequently complained to the dealer or pit. That may have flagged you as someon to watch for. It could have been another ploppy, or even another AP and your jumping in just ate away at the rich deck the AP has been waiting for. If you continued to do it and they figured you were backcounting, they decided low roller or not, they didn't want/need your business.

There's nothing wrong with backcounting to gain an edge. How you do it and handle yourself in the casino environment is critical. Also, no point trying to defend yourself saying you're only playing Basic Strategy and wish to speak to a Manager. Just leave.