Do you have thisupdateonAppleAppStore?
SinceI oftenam askedtomigrationmavericks!
I find it veryannoying.Andnot correctfromapple
I am in complete agreement with you.
Please see this discussion: https://discussions.apple.com/thread/6016792?answerId=25316504022#25316504022
Some of us have been subjected to this. In my case it was even installed without my knowledge, perhaps during a visit to the App store. (Only happened on a Mini running SL. I have not yet checked my MB on Lion. Of course it will not happen on my MBP that is already running Mavericks.)