In reply to Lenin Zapata.
I agree completely here and we have tried very hard to not make this a complete limitation.

What I really want too is for them to be less annoying, just as you say. I hear from other theme authors often when they feel like a certain theme they have seen has gone over the top with their activation notice. What is worse though is that I regularly hear that same complaint from end users that are actually trying out the themes for their own sites :(

If the activation notice appears in the notice area then they should look like a notice – similar to the existing core notice look and feel. Users shouldn’t be conditioned to expect these to be adverts but that is what I see happen too often.

People are welcome (and encouraged) to explore what is possible here and we can certainly reevaluate constraints again if that is what I end up hearing needs done :)