Perhaps they were afraid of legal issues ?

scraping for fun is okay, but if you would like to build a business most people would prefer to abide by the terms of use and still use the API. remember the story of Pad Mapper ?

Or an alternative API that uses the scraped data from Twitter to make requests... but that might be getting a bit ambitious (and legally dodgy)

Create an script that scraps proxies and then use those to scrap twitter, use it in a Russian domain, claim 140 characters can't be copyrighted, claim that the tweets are being extracted from third party sites that use the twitter API but lack any kind of TOS and disclaimer; sell API access, profit!

I've written some in-browser JS to download all my tweets without needing to resort to the API and oAuth nightmare. It is indeed possible to write a client, but not recommended at all...

how did you send cross domain request?

if they really needed that much data they probably just requested access to the full phirehose