Go easy on the lad!
Nothing wrong at all using public/free proxies to scrape with, I find a LOT of good ones to use, but OP, you have to test the proxies first and only use google passed ones.
Lately I've actually been thinking that the proxies that simply turn out as Anonymous can be used to scrape with and the fact they don't google pass is either they're temp blocked or it's a false negative.
When things went wrong and the developers had to make updates because of the proxy issue, almost no proxy would google pass, though a decent amount would be labeled Anonymous, and I was able to scrape using the Anonymous proxies that failed the google test.
SB is both great for/with proxies and very stubborn, which I guess is why I like it so much.