The most important point about Android is that apps can be installed from third-party sources just by toggling a switch in the settings on the stock firmware.
While Google probably technically could use the remote uninstall function on an app not installed via their Market, it seems extraordinarily unlikely that they would. And as you suggest, there already exists CyanogenMod and other third-party firmwares; it's fairly easy to strip Android of any connection to Google if you so desire.
While Google probably technically could use the remote uninstall function on an app not installed via their Market, it seems extraordinarily unlikely that they would. And as you suggest, there already exists CyanogenMod and other third-party firmwares; it's fairly easy to strip Android of any connection to Google if you so desire.