I'm sure it's protected against incorrect sequencing since the spec states that if you float the PWM input wire, the motor runs at full speed. I would assume if there was a hint of sequencing dependence, the motor would not run without a robust signal. It should be a brick if the input signal was grounded or floating. Probably even shouldn't run if the input was a steady voltage instead of a true PWM...but who knows how that driver was designed with safety features. But yes, thanks for the reminder about proper sequencing.