It is bulls*** and I say it again, for the second time.
There is no bond, only the deduction of 415 euros for 36 months.
After 3 years you get back 7500 on the 37th month salary.
If you leave before 36 months you have to give them back 15000 minus what they already deducted from your salary. That is what you call bond.
It's been like this for at least 6 months, I dont know before. I talk about people not type rated that got the TR from Wizz.
End of story, no rocket science.