Incognito browsing is grossly misunderstood.
A careful reading of the Google site shows:
(1) When you browse privately, other people who use the device won’t see your activity.
(2) Chrome doesn’t save your browsing history or information entered in forms.
(3) Cookies and site data are remembered while you’re browsing, but deleted when you exit Incognito mode.
Sounds good, but the Google site also shows the bad side:
Your activity might still be visible to:
(1) Websites you visit, including the ads and resources used on those sites.
(2) Your employer, school, or whoever runs the network you are using.
(3) Your internet service provider.
The word “might” above means that: your Incognito data is there for anyone who whats to see it. All they have to do is just look for it, just like they usually do.