Personally, I've never put anything into warm ups. Some guys seem
to take it fairly seriously, some guys are out there to just goof
around. Generally speaking, IMO it followed the same patterns
of their play, some guys out there ball to the wall every point,
other guys who mail it in as often as not.
Your friend's loafer theory fits with one of my favorite goofy
betting angles from back in the days. When Behretche was playing
at Dania he was pretty much notorious as one of the laziest and
biggest goof offs the roster had. Every once in a great while
he would come out to warm up with the cesta on his left hand,
surprisingly, he was actually pretty good playing with the basket
on his off hand, at least warming up. The odd part was that nearly
every time he came out and warmed up like that, he hit the board,
and hit it with more than his fair share of wins. Soon enough
that became a known betting angle among the people who were Dania's
hardcore regulars and every once in awhile you'd hear one of them
yelling "put the basket on your left hand Behe!" during
warmups.