40k coin tosses yield ambiguous evidence for dynamical bias
From a physics stand point, coin tossing is similar to knife throwing or axe throwing.  It's completely within human capability to intentionally or unintentionally time the toss with some degree of accuracy.  I doubt anyone can be "good" at this (otherwise it would be a great grifting trick), but surely this creates at least a marginal bias in the data at a high enough scale.