Ok, from my experience (which mostly getting banned because events unfortunately) there are some clue on how to stay out of radar :
1. Don't be greedy with event chest.
multiple chest being opened in short time might get you banned. In fact, just keep your goal on opening 10x chest instead.
2. Chapter 2 or 3 event might make you sus.
If possible, control yourself completing chapter 2 halfway only.
3. Beware of your statistic/status !
Most rank 15-13 (my best) still only have about 10-15 continuous win.
A new player don't (usually) have full team of Legendary.
Almost no losing statistic. That kind of thing.
Hope this would make you survive at least a week.
