This still doesn't explain why it should be a percentage other than that everyone assumes a percentage.
This word is telling. If I go out to dinner I'd really prefer to not be hustled.
hus·tle ˈhəsəl/ verb
1.
force (someone) to move hurriedly or unceremoniously in a specified direction.
2.
North Americaninformal
obtain by forceful action or persuasion.
3.
North Americaninformal
engage in prostitution.