Nope if you have full protection you always get back the full value of your holdings (in this case, YFI) as if you held them in your wallet + swap fees.
The nuance is when withdrawing your liquidity some of IL protection may be paid out in BNT, depending on how much YFI is available in the pool. In this case, you can just immediately convert the BNT back to YFI.
Example:
- stake $100 worth of YFI
- YFI price 2x & LP stake now worth $200 (ignoring swap fees)
- LP experienced some IL, but achieved 100% protection
- when LP withdraws there are not enough YFI in the pool to compensate LP fully in YFI
- LP receives $170 in YFI and $30 in BNT