There have been whole AdSense accounts bringing in $5000 per month banned for life from Google because of fraudulent clicks. If Google catches you clicking on your own AdSense ads, they can shut you down.
You won't get canned just for a single click, but if you're like me and tweak your site a lot it's only a matter of time before you click on one of those things by accident.
The way I keep this from happening is I temporarily block the domain name Google's ads are served from. Once I'm finished editing my site I go back under the hood and turn it back on.
Getting this setup will take you less than a minute.
First, find your HOSTS file.
Open Notepad. Go to File, and Choose Open.
If you have Windows 95, 98, or ME browse to the folder "C:\windows"
If you have Windows XP Home browse to the folder "C:\windows\system32\drivers\etc"
If you have anything else (Windows XP Pro, Windows 2000, NT, 2003, etc.) browse to the folder: "C:\winnt\system32\drivers\etc"
Once you're there, open the file called "hosts". If you don't see anything listed just type the word hosts and the file should open up. Just the word "hosts", no extension or anything after that. It's probably blank but it might not be.
Add this line:
127.0.0.1 pagead2.googlesyndication.com
And save. You're done.
Now go back to a site that you know has some Google Ads. There should be an empty space where the ads appeared.
Want to turn it off? Don't just delete it, put a "#" sign in front of that line, like this:
# 127.0.0.1 pagead2.googlesyndication.com
What's that do? It basically says "ignore this line." I like to leave it like that so when I want to hide Google Ads again, all I have to do is remove the "#" sign and save