Open Source Licensing – Retaining Rights to Revoke Usage

From your comments, it appears that you're looking for a way to license a library that you wrote so you can use it in a proprietary project but still have the license be GPL-compatible.

First off, this is a bit nonsensical. The GPL carries a whole lot of anti-proprietary-software ideological baggage with it. It's designed that way; the whole point of it is to make it as difficult as possible to integrate GPL or LGPL code into a proprietary project.

However, licenses are for other people. They don't apply to the copyright owner, which is you, the person who wrote the library. You can use your own code however you want to, regardless of the terms of the license you put on it. So you can make it GPL or LGPL and still use it in your proprietary project and you'll be fine.

On the other hand, if you want people in general to be able to use it in GPL projects or also to be able to use it in proprietary projects but still be required to publish the source to whatever changes they make, try dual-licensing it as (L)GPL and MPL.

My specific question is "how do you select which one you want to use." In my case, I want to only use the BSD license and I want to make it explicitly clear that I do not opt into the GPL v2 license in any way.

You just do. Unless you don't change the source-code there, you don't even need to touch the plate. It can be stayed as is, yes, even touching it for no reason might look more suspicious then just leaving it as-is.

The licenses are offered to you btw. Into which one you opt, you can say anytime, you can choose anytime which one. The one day you might like BSD and the other day you might even use GPL. Both is possible. You can even choose both, even if they both would be incompatible to each other. Only based on the fact the original author(s) did dual-license it.

How do you do that and have it hold up to legal challenge?

No-one can predict the future, but keep references of the websites of today, so that you can document that you've taken care and you can back-up your statement that the dual-license is disjunctive (OR) and not conjunctive (AND).

As long as it's clear that you were allowed to use the software under the terms of the BSD license (and you fulfilled the requirements) I see no reason why it shouldn't hold up a legal challenge, I can not even imagine of which kind such a legal challenge would be?