I just clicked on What's App on my Android phone to send a message and then it asked me to backup my Chats (messages) and Media on Google Drive.
You have a choice (lucky enough there's NEVER in the selection). Why would I do that?! Am I the only one noticing this?! Like WTF!!
https://www.whatsapp.com/faq/en/android/28000019 Important: Media and messages you back up are not protected by WhatsApp end-to-end encryption while in Google Drive.
EDIT To ensure you are not backing up to your Google Drive:
+ Click on the three dots top right corner + Click on Settings + Click on Chats backup
There should be a Google Drive settings