Humankind has a natural inclination to avoid pain. If UK votes to leave and it threatens other countries' economic stability then other countries will do what they can to alleviate it.
There is punishment and there is mutually assured destruction. It's much like the cold war. Threats are made but when fingers are on buttons they will waiver and deplomacy will take over to avoid net sufferance.
I cannot believe that the EU, whose behaviour has constantly displayed a 'whatever it takes' response to survival, would let a Brexit vote paint themselves into a corner of sufferance.
As any parent knows, threats of punishment before the action are a different matter once the action has taken place. Negotiation and compromise is still most likely.
If we seriously think that,as the FT has suggested, the likes of the Mexican Peso's fate is in the balance of Brexit then something is messed up. Shock is one thing but reality is another. The tertiary correlations should be faded.
Look at this as the Cuban missile crisis. Sense will prevail to protect the majority. If you don't believe me look at the response to the global financial crisis. The masses were forgiven their debt to preserve society.
Position update.. started trimming GBP 1.4000 Sept puts. Watching FTSE to buy. Will buy EM such as MXN that is being slammed on tertiary Brexit arguments. Running short BTPs as that is going to be a slower burn Euro woe.