Short answer: No. Long answer: You
can change it.
*I assume you are talking about the Develop->Empty Caches item? (Option-Command-E) Amazingly, the System will allow you to add a shortcut in the Keyboard System pref in Safari! I would have thought it would have at least complained. However, it may be related to the fact that Safari doesn't even show that shortcut unless you enable the Debug menu. If you don't use that much, try just disabling it?
* Change it to something else? System Prefs->Keyboard->Shortcuts. Select "App Shortcuts". Click the "+" button and select Safari from the list of apps. Type the exact name of the menu item you want to edit ("Empty Caches") and type in a different, seldom used(?) combination.
I was able to change that combination to (Option-Command-T), choose combination that's not already being used. You don't even need to Quit Safari!