"Hey Wellington, remember that little battle at waterloo? Well, yeah, y'all beat us up pretty badly. But you know, I never intended for the battle to go that way and I never intended for you to deprive me of my reign. And that little incident on the Bellerophon? Well, I decided that you pretty much had me surrounded so I was coerced into your exile plan. I decided I don't like it on Saint Helena anymore, so call up Castlereagh and tell him the Paris deal's off. And he can communicate to Metternich that I want my empire back since it was unlawfully deprived of me by the duress you placed me in."
Lousy example #2. Napoleon surrendered to the Brits fearing for his life if the Prussians or French monarchists got hold of him. He'd already abdicated his throne and was a mere prisoner, unable to negotiate anything. Sorta like Santa Anna.
There is, by the way, some opinion that Napoleon's exile to St. Helena was illegal, a violation of British law since there was no trial or other legal proceeding.