Industry question: competition clauses

I read with some amount of trepidation the post about competition clauses in publishing contracts. How does someone deal with a potential offer to publish something when one  (OK, me) has already self published a series of books with the same characters? There might be rioting in the streets (OK, a couple of middle aged women hanging out at the National Zoo panda house) if my other books had to be pulled off the market.

Here's an example of a competition clause in a publishing contract:

the Author will not, without the Publisher’s prior written consent, publish or authorize publication by

anyone other than the Publisher of any text-based edition, adaptation, abridgement, or

condensation of the Work, or of any text-based derivative work based on the Work or bearing

substantially the same title (prequels and sequels shall not be deemed derivative works) (however,

nothing in this subparagraph (i) shall prohibit the Author from disposing of performance rights); (ii)

the Author will not publish or authorize publication of any similar material on the same topic in a

book or article which, in the Publisher’s judgment would directly conflict with the sale of the Work,

provided that, subject to coordination with the Publisher, nothing contained herein shall preclude

the Author from publishing or authorizing the publication of articles to promote or publicize the

Work; 

If I sell your novel "Felix Buttonweezer Goes to Carkoon" to LicketySplit Publishers LLC, you cannot sell an adaptation, abridgement or condensation of the book to another publisher. 

Nor can you sell "Felix Buttonweezer Went to Carkoon but Now He's Home" which is a derivative work.

Which does mean, yes, if you have self-published the novel that I sell to LiSP LLC, you're probably going to have to take it off the market.

However.

Contracts are NEGOTIATED. They are not handed down to supplicants like the ten commandments, no matter how many trumpets and rings of fire the publisher would like you to believe accompany its arrival in your inbox.

If you've got works for sale that are related to the novel for sale, you'll tell me about it ahead of time, and I'll tell the editor and we'll discuss how to handle it.

This clause predates the burgeoning cottage industry of ebooks on Amazon. It was intended mostly for non-fiction books. Editors didn't want to buy "The Bakeries of Carkoon" only to find much of the content of the book repurposed in "The Food Trucks of Carkoon."

This is something you do NOT need to worry about until you have an offer of publication.
It IS something you'll tell your agent about before your work goes out on submission.

You do NOT want to be the author who keeps her agent in the dark such that the editor calls the agent with the very bad news that something that looks a lot like this book on submission is already for sale on Amazon.

Yes, this happened to me.
Yes, I was royally pissed.
Yes, the client is no longer my client.
Yes, you can learn from her tomfoolery.