As long as they aren't in crunch time 365.25 days of the year, or of course all that often, it's OK.
In fact, by specifically calling out such a thing as "crunch time", you can ask them "how much of the month/year do you spend in crunch time?", the answer to which should be very telling.
In fact, by specifically calling out such a thing as "crunch time", you can ask them "how much of the month/year do you spend in crunch time?", the answer to which should be very telling.