Thanks for the responses
Looks like several players have had the same experience. I thought I was relatively safe since there was another player at the table betting many times my average bet. I figured they'd be watching him instead of me but clearly I was wrong. I was way behind early in my session, I think I lost the first 6-7 hands, so I felt it might be OK to throw a four chip bet out there when the count was very positive in an attempt to get my money back. Usually I only increase my bets by parlaying a win but this doesn't enable much of a spread on a single deck game where you're only getting two or three hands per shuffle. I also figured, incorrectly, that since I was losing they wouldn't back me off. The only other place I've been backed off while LOSING is the Barbary Coast in LV.