yeah NBA players are too busy to get arrested, they have stuff to do like go into the stands and fight the fans.
But as far as comparing NBA players to NFL players isn't the same. To me it seems like the more higher profile athletes get in trouble in the NBA than the NFL. Most of these NFL players that get arrested now are mostly low profile players, Mike Vick is the exception. Look at the NBA, Kobe, Carmelo, Jason Kidd, Allen Iverson, Chauncey Billups, Marbury, Jermaine O'Neal, Rasheed Wallace, Jason Richardson, Joe Smith, Gilbert Arenas have all been arrested.
A lot of this can be attributed from lack of time in college
Link
"Players going to the NBA after just one year of college have
been arrested at a 21% clip. Sophomore's have been arrested
at a 46% rate. While percentages show that leaving college
after three years creates a 40% chance of being arrested.
However, the rate drops significantly for college graduates. A
mere 14% were arrested during the same time period and under
the same research guidelines."