For decades in the States, where most of the litigation has gone on, it has not caused problems. You can't.... How is one supposed to find the time to marshal their case and then start multiple proceedings? That's not the way the real world works. They're going to pursue the avenue that is most effective and most efficient and will give them a chance to prevail.
It just doesn't happen. It wouldn't be fiscally feasible for a whistle-blower. It is a comment that comes up, but it's just not supported by real-world data.