I've been contemplating the thread ("ooops") that started with a Snarkling asking if agents alerted clients ahead of time about where their projects were being submitted. I said no, and got some flak for it along the lines of "why not, it's just an email".
Late last night I got an email rejection from an editor who'd had the novel for awhile. Naturally I was at my desk to receive the email and whip one right back to him with a suggestion on another book. Now, the second author was, I hope, snoozing merrily away and dreaming sweet writer dreams, while all this happened. Was I going to wait till morning? Was I going to call the author? Answer to both; Hell no.
This is my job. It's not yours. Your job is to write. Bottom line: if you have some sort of rock solid requirement that your book not be submitted to publishers who did an OJ book (of course I've seen that) or who aren't owned by Germans (that too) or who do not employ your ex spouse/lover/dog (ya, ya, and well no, but close) you gotta mention that upfront.
One of the books I sold last year was cause I happened to mention it to an editor at a party who I thought would have NO, zero, zippo interest. Turns out her publishing house was launching a new imprint and my book was perfect. There was no way to know ahead of time that I'd be submitting to her. Was I going to call the author and say "this new publisher is interested" and then withdraw the submission if the author quibbled? Again, and with fervor: hell no.
It's not been my practice to ask clients if they have such requirements, I may have to start doing so. Mostly my clients just hand me the manuscript and say "call me when you've got an offer".