High deposit int rate / currency pegged to $

Lebanon has been pegging it’s currency to the US dollar since 1997 (1 USD = 1,507.5 L.L). Banks offer interest of around 6-7% on deposits in Lebanese Lira.

If one was to invest at these interest rates, what are some of the best indicators that could indicate that the peg might fail and the country might be forced to float their currency? Decreasing foreign reserves etc.?