I think just experienced what might be the mildest counter-measure ever. I was sitting one spot left of FB and alternating between playing that spot and playing both that spot and FB. I saw a pit critter in a position to be watching me, but dismissed it as paranoia, since I don't play high stakes and have never gotten any heat at this store.

As a very positive shoe came to an end, I had big bets on two spots (lost both bets, incidentally). Just as the cut card was about to come out, a pit critter (not sure his role - thought he was a regular floor guy, but could have been higher up) pops over, looks at how many cards are left in the shoe, and says something as quietly has he can to the dealer. Since he was standing by the shoe and I was near FB, I could hear more than he wanted me to. I'm pretty sure he said something like "I need you to one-hand this guy." The dealer seemed surprised and a little taken aback and I heard her response clearly: "Spot 1?" Pit critter says "yeah".

Is "one spotting" someone a thing? I've never heard of this before. If it is, it's a pretty mild counter-measure and I assume it's designed to give you the hint that you've played long enough, rather than actually making it so you can't make money.

I'd been about to leave anyway, so colored up and headed for the nearest exit; probably I should have stayed for another shoe (and seen whether penetration changed) and flat-bet to give the pit critter a reason to doubt himself. What would you have done?