hec7tor,
That's true. But the risk is not as great as when all communications are deliberately obscured by unnecessarily switching to a completely unintelligible language for everyone else. Every time.
One is a tiny and rare risk. The other is a huge and omnipresent risk. Geddit?
A German aircraft and a French aircraft fly together all the way across Europe to CDG. All the way, all comms is done in perfect English.
As soon as you switch to CDG, the French controller and the French aircraft speak French, and the French controller and the German aircraft speak perfect English. Now the French and German aircraft cannot understand the instructions between the other parties - purely because of French pride. NOTHING ELSE.
National pride before safety of pax is not acceptable in modern aviation, however proud you are. That's the point.
The Dutch have it about right. Any chat at Schipol is done in Dutch. But all safety critical comms (clearances and so on) are done in perfect English.