Here's my thruppence worth
1. Exposure is generally considered as bad form, even in the context that you have used in your example. Generally, what would perhaps occur is that when an explanation is given, it would be a false explanation but one that was convincing enough to those that think that they are now in on the secret. An example of this is perhaps Derren Brown as in a number of his TV shows he has given explanation on how he achived something which have then been debated long and hard by magicians, some on this forum. Was the explanation, despite it sounding plausible, no more than a red herring?Then there is always an exeption to a rule and Penn & Teller revel in exposing how certain effects are done.
2. Speaking vs Silent acts is a choce of performance. Some effects perhaps suit silence wheras others don't.
3. Many respected magicians have done the former apart from Geller. It's perhaps what the magician him/herself wants to achieve. Others may not make claims of trickery but done claim special powers either. They leave it up to the audience to decide instead and perhaps add a little mystique to keep them guessing.
I've probably now stirred up a hornets nest

Member of the Magic Circle & The 2009 British Isles Close-Up Magician of the Year
It's not really an optical illusion - it just looks like one!