Hi, Ajinkya!
Today's Saturady, my lawyers don't work on weekends -actually nearly neither on working days-, so I'll quote myself from an upward post:
"Actually I even don't knot what that verb hac.? means (I guess something about those guys who use axes), and so I've never done such a thing before (whatsoever it means, of course), I love trees. And I'd never do it again until next occurrence."
There's always the chance of being hacked, no one is fully safe, it's just an equation about cost vs. benefit issue, if nothing personal is involved.
It'd depend on the interest you might trigger, the valuable data you can be stolen, actually it depends on who are you and what do you do. If you're not considered a target, much that despite your ego, you'll be reasonable safe.
The other point is your security concerns and how you interact with the internet. If you use shared computers and tell browsers to remind your Id and password for web services, if you fulfill all the data required by forms with your actual data, if you write "I'm going to have dinner with my son Charles" or "My dog Duke is lovely" at social networks pages and you use those names or other related info as birthdates or so, if you use the very same and easy password for all services, ... if you do all that you don't have to do, well, you're shouting out "come for me, here I am!". If I were not so polite, perhaps I'd say that you want to get in trouble, and if so then you deserve to -if not be hacked- at least got compromised in your security. Just for learning the lesson by the hard way. Same as with backups, almost no one supports a full restore of your data as part of the test of a contingency plan, most people do it partially and others don't, until they lose all info, then they began to burn 2 DVD everyday, three months later you have 100 DVD, with a little information redundancy.
About your GMail question, I honestly don't think that DNT+ helps to avoid being hacked at all, it's intended for other purposes, just to don't be tracked. Enter to the website and read what it does, how it works, and what actually means tracking.
Regards!