You’ve got a trip scheduled, say a vacation or technical conference, and you’re looking forward to it.
If the company asks you to cancel it because now’s not a good time to be out of the office, should you?
Is there ever a good time to be out of the office?
When do you bend, vs. drawing a line in the dirt and saying you won’t cross it?
I’m just asking the question.
Seek Nuance 
Bummer. Don’t they realize how much you look forward to that every year?
You still do work while you’re there too, right?
Bastards.
It’s not me. I’m asking in regards to a friend. (Honest.)
Oh, hell no. Explain politely that [your friend] has been refused permission to cancel.
Fuck ’em. When your employer is through with you, they’ll pass you by like week-old roadkill. While you’re away solicit and entertain employment offers like there’s no tomorrow….because there isn’t.
Corollary: Take all vacations during peak periods of system instablity. It’s the only way they’ll notice that you’re gone. If they object, setup an immediate meeting to “negotiate your compensation”. Bring a handgun and sport a crewcut.