They didn't touch the cards, This type of card marking is stereotypical of Chinese males (they have been doing it for decades) and what I'm about to say is unbelievable. What they do is find the right table conditions, Timid or easily manipulated dealer, Floor and PB not paying attention...then they start working themselves into a frenzy, being loud, shouting "Monkey", banging on the table...Then they take chip in their hand and blaintently slam the chip down on the selected card.
How they get away with it for any length of time is beyond me...Seems like an easy catch to me. Ive seen this done only twice and both times were in AC.
EXGM