You can always give employees more pay, more vacation, better health care and so on. No union will prevent that. It just guarantees the absolute minimum levels.
What Tesla does is just plain stupid, only to make a point about opossing unions...
3. Call-out
Call-out means work for which the employee is called back after regular working
hours and after having left the workplace.
3.1. At least one hour’s salary and a call-out pay shall be paid as follows:
a) If the employee was called after regular working hours or on the employ-
ee’s day off but before 9.00 pm, the call-out pay is equivalent to 2 hours’
salary.
b) If the employee was called between 9:00 pm and 6:00 am, the call-out
pay is equivalent to 3 hours’ salary.
3.2. If the work in case b) above represents daily overtime, the overtime com-
pensation for call-out work done as overtime work is immediately 100%.