Bit.ly ads sneaking past Adblock Plus?

I can't stand ads. I don't like them on TV, I don't read magazines due to the rampant advertising, and I definitely don't like them on the web. I've been using Adblock Plus for several years on Firefox and more recently on Chrome. I even run AdFree on my rooted android phone for system wide adblocking. Today I saw an ad, though. While blocking it I noticed something very unusual - the URL of the banner was on bit.ly. As this type of URL shortening service creates essentially pseudorandom URLs this seems like the perfect ploy to defeat Adblock.

I worriedly searched Google but I haven't found any information. I sure hope that one lone ad wasn't a canary in the coalmine of obnoxious banners returning to my web viewing experience.