EU Withdrawal - inconceivable peacefully post-Lisbon?

Think about this quote from a Reuters report on Canada.com linked here:

"We are concerned that Serbia is slipping away," Bulgarian Prime Minister Sergei Stanishev said in Brussels in a comment to Reuters ahead of an EU summit.

"The political situation in Serbia is creating an atmosphere of national rhetoric...which means possibly in the end Serbia would voluntarily isolate itself from the EU."

Now consider this reference in the House of Lords Impact Assessment on the EU Reform Treaty:

2.68. It is significant that the Lisbon Treaty adds to the Treaties a clause confirming the right of a Member State to withdraw from the Union, and also sets out the procedure it could use to negotiate a withdrawal.

"Could" Ideas of what they might mean by that on a postcard please! Consider the following: 1. Before Lisbon, or certainly before the European Communities Act 1972, as a Sovereign State nobody could argue that we had the absolute right to withdraw from any Treaty. 2. A State wishing to withdraw after the Lisbon Treaty, if ratified, would presumably presumably be in "dispute" with all the other members, namely it is being unfairly victimised or acting unreasonably. But there is no disputes procedure so withdrawal is its only option - But the terms of its being allowed to withdraw will be set by the parties with whom it is in dispute AND it will be excluded from these considerations. 3. This is equivalent to any commercial contract or arrangement having no arbitration clause or reference to legal jurisdiction merely a stipulation that the bully will determine the terms of the settlement of the dispute. 4. If Malta withdrew it would probably be stuck with the terms laid down, a larger country such as the UK "could" threaten nuclear retaliation or some such, but why would any nation wish to put themselves in such an unhappy relationship with its neighbours? Especially when they are as clearly ill-intentioned as those presently prepared to force through such a deceitful and conspiratorial arrangement as the EU Reform/Lisbon Treaty. I have always suspected that one of the worst aspects of this Treaty could well prove to be this withdrawal clause, as if the nation states retain any pretence of sovereignty it should be redundant. Hopefully the House of Lords debates will throw some light on this. Meantime it looks like clever Serbia, I would say, if only the UK could have one simple vote on 11th May and thus 'isolate ourselves' from the EU as it is being constructed under the "CONSTITUTIONAL TREATY REBORN"