SIP is another IETF gem, which takes its syntax from HTTP. And guess what? It's impossible to have unambiguous parsing in the wild! Why? The whole liberal in what you accept bad idea. So A interprets \n as a line ending, even though the spec says \r\n. B interprets it another liberal way, and assumes you didn't mean to transmit two newlines in a row, so it'll keep reading headers. End result: you can bypass policy restrictions by abusing this liberal-ness and get A to approve a message that B will interpret in another way. Yikes. And, since the software for both is so widely deployed, there is little hope of solving the problem. In fact, the IETF essentially requires you to implement AI as you're supposed to guess at the "intent" of a message.
So you're sorta proving my point, that people are thinking "oh it's just text" and then writing shitty, sloppy code, and they're giddy cause it sorta worked, even from a two line shell script. And then further generations have to deal with this mess, because these folks just can't bear to get line endings right or whatnot.
