Continuity mistake: The getaway car changes from a Peugeot Partner (1996-2003) to a Citroen C3 Picasso (2013-2017). (01:35:30 - 01:36:05)
Continuity mistake: When Nicky and Jess are seated at the small table, the amount of wine in his glass keeps changing up and down.
Continuity mistake: The amount of blood on Nicky's chest when he is shot by his dad changes between angles.
Answer: Absolutely. There are many people (especially people who work on high commissions and con men) who are well practiced in subtle cues with body language. The elaborate process they went through in the movie greatly increased the chances he would make such a pick, but there was no guarantee. However, it was constructed with personal knowledge of the target. Even more strange was the fact that a string of some of his reasonable bets went bad (the missed extra point, the pick of the card, etc). Had they all not gone bad, it would have disrupted his faked desperation to the multi-million dollar bet.