Since Julie blogged about a call to her home from a student who wanted to add her class, I thought I'd add a story of my own, from waaaay back:
I was in the second year of my chemistry graduate program, TAing the thermodynamics course for chem majors. One of the students in the class had been a friend of mine for five years -- we taught together at math camp. That was a little weird (grading someone with whom I was a professional equal only two summers earlier), but not impossible.
Her boyfriend was also taking the class. And he got the bright idea, the night before one of the problem sets was due, to call me for help with the problem set. At home. At like 11:30 PM.
Though asleep, I answered the phone (after who knows how many rings -- we didn't have an answering machine at that point). It took me awhile to wake up enough to actually become aware of the nature of the call. He was shaking me down for answers during my sleep time!
When I finally realized this, I was pissed. As politely as I could, I told him I was off-duty and asked him not to call me at home agin.
Here's the kicker, though: I have a history of talking in my sleep, even on the phone. (No joke, I have agreed to detailed dinner plans on the phone while napping, waking from the nap with no recollection whatsoever of having made the plans.) And when I'm asleep, the things I say are not tethered to reality in the same way that they are, say, during my office hours. So during the 10-15 minutes I was not yet awake taking on the phone with my friend's evil* boyfriend, there's no telling what crazy version of thermodynamics I may have been relating to him.
And really, for calling me at home so late the night before the problem set was due, bizarro-thermo would serve him right.
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*I make no claims about this guy's evilness qua boyfriend. I'm comfortable asserting, however, that using a personal connection to get the home phone number of your TA and then calling her at home late at night is an evil thing for a student to do.
I do crazy stuff in my sleep too. Last week, I feel asleep on the couch, and when I woke up my laptop that I was doing work on was in the shower (dry as a bone, luckily). A few years ago while I was in college, I apparently vacuumed a huge rug in my fraternity house around midnight in my boxers while still asleep.
Hopefully patients never call me for medical advice when I'm sleeping!
A lot of faculty end up getting unlisted numbers because of calls like that.
With cell phones it gets worse.
My solution is to spell out in detail what my better half will do to them if they call me at home and wake up a munchkin. Worked so far.
I had a colleague who once got a call form a student at 2:00 AM the night before an exam. And her number was unlisted.
How do you feel about Ph.D. advisors who call you at home at 11:30 at night, weekdays or weekends? I used to get calls from my advisor regularly for updates on the research, random questions about papers, and solicitations for help with Microsoft Excel.
Our department secretaries used to give out my home number to just about anyone who asked. I always thought that they wanted to avoid having students get the idea that they (the department secretaries) were responsible for helping students.
What about the ethical implications of having a friend as your student? At my school, you can't TA a section if you know any of the students outside of class. Either the student or the TA need to change sections. If there's only one section, I'd imagine they'd let the TA continue TAing the class, but they'd probably encourage you to TA a different class.
Don't think that it changes if you are out in the corporate or freelancing world! When I was in corporate service, I got phone calls from our division chairman (easily 8 seniority steps above me) at home in the evening to check on the status of projects that his immediate underlings told him were going according to timeline. I would walk him through when things would be done in my shop and they would all happen per the timeline, just like I had told my bosses. The idea that I was on call 24/7 for this guy was just too irritating, we started having the machine pick up during the evening just to avoid him.
Now, as a freelancing writer/editor, my clients seem to think that they pay for my time no matter what time it is, what day of the week it may be, or whether I've told them I'm out of the office or on vacation! However, I have a client in Japan who, due to our time differences, often calls in the evening; she is soooo apologetic when she calls that I don't get cranky, but trying to understand her English (as my Japanese is non-existent) at 11:00 p.m. is sometimes very challenging.
What's the point of an unlisted number if, as a laboratory supervisor, your contact details are posted on all the doors and safety sheets as an emergency contact?
I give them my cell phone number, and I turn off my cell phone when I go home.