I like this stuff. It reminds me that humans with a sense of humor build the things we use everyday, and not some emotionless robot.
Having said that, people do get upset about 0xDEADBEEF and 0xCAFEBABE, those people need to get lives. Or come up with some other words using only 6 letters.
I'll wager someone out there, perhaps unwittingly, has 0xDEADBABE in their binary, God help them if the twitterati finds out.
If you are have no public talking experience/training, you are going to loose and be labeled ugly names.
GOAWAY makes plenty sense when compared to GTFO, assuming that not everyone who learns of it intentionally is well-versed in that of which GTFO is a relatively smaller part. Grandma wouldn't necessarily get GTFO (right away, anyway) but she would likely pick up GOAWAY in a snap.
Of course, the above assumes a section of people who are fluent (enough?) in English to grok the spec.
EDIT: Grammerr.
EDIT: Clarification in response to Vonmoltke.
English profanity has a tendency to be better understood by other languages and countries than the appropriate western vernacular.
Oh, STFU.
Seriously, though, I see the point. I'm kinda torn on issues likes this. On one hand, language in a standard, particularly as it relates to implemented messages, should meet some minimum level of decorum and avoid colloquialisms. On the other hand, stuffy language battles are pointless and distract from the primary goal of releasing a usable standard with usable error messages. On this particular issue I lean towards the former winning out.
Edit: someone else mentioned the word I was trying to think of.