Windows has an existing convention for this, like Linux's XDG. Imagine if you looked at your Linux filesystem root and saw /boot, /dev, /usr, /tmp, and /Quicken.
I mean, honestly, I would be somewhere between "somewhat miffed" to "laughing out loud" if I saw /Quicken. It would not surprise me in the least to see something like Quicken completely violating standards and/or good taste.
You'd probably see a /Quicken/ as well as a file /Quicken-uninstall as a broken symlink to nowhere.
You'd probably see a /Quicken/ as well as a file /Quicken-uninstall as a broken symlink to nowhere.