Well, adpreview tool SUCKS!
The reason - i like to see the competitors landing pages and in adpreview links are disabled.
Google claims they filter out most of invalid clicks – year right!
I was logged in to my MCC, I have a google toolbar installed to see PR. I clicked on my own add, by the way the only click that day for that keyword and google did NOT filtered that click and i had to pay for it.
If google can’t detect that - I feel adwords filtering is a joke! ( I don’t use proxy to change my ip)
Now, I check my competitors’ ads/pages daily and sometimes I click several times to see landing pages under different keywords – just part of the research. And I know my competitors keeping an eye on me also. AND all of these clicks are invalid! My competitors should not pay google for my research, I will not buy anything.