I think the obvious solution is to have the client first check for updated scraping rules from a server operated by the client's creator. The client could check

I think the obvious solution is to have the client first check for updated scraping rules from a server operated by the client's creator. The client could check for these scraping rule updates every time the client starts up or on some interval (or maybe after certain errors even) and only pull down the whole thing when the cache is invalidated. Then, as you suggest, the client could do the actual scraping which would make it harder for twitter to block. Not as straightforward as an API to be sure, but not impossible by a long shot.