A thought tickled my brain, and I thought I would share, even though it might not help..
I was dealing with compressing and decompressing data via Compress::Zlib, and doing some research. Apparently browsers are smart enough to take a compressed data stream from a server, and decompress it locally!! So, with that being said, it would stand to reason to get garbage everywhere except for a browser, if the browser were in fact decompressing prior to output. Now that was also in regards to the total HTTP transmisson, but I wouldnt put it past them to auto detect compressed data and simply decompress those components of the transmission stream..

Might help, might be worthless, happy hacking

/* And the Creator, against his better judgement, wrote man.c */