Editor's note: Inc.com columnist Alison Green answers questions about workplace and management issues-everything from how to deal with a micromanaging boss to how to talk to someone on your team about body odor.

A reader writes:

Can the company I work for tell us that we have to answer our cell phones while we are on vacation? I asked if I would get vacation time back if I do, and the answer was no. They say because they pay the phone bill, we have to answer the calls no matter what.

I thought the purpose of a vacation is that you unplug from work.

This is one of those issues where the question of what's legal is different from the question of what's smart.

Let's tackle the legality first: Yes, in the U.S., it's legal for your employer to require this. Because no law requires employers to give paid vacation time, your employer can structure the paid time-off they offer however they like: They can say that you can take the time as long you answer your cell phone, or as long as you check email once a day, or as long as you perform an interpretative dance report on your vacation when you return.

I confirmed this with Bryan Cavanaugh, a St. Louis-based employment attorney, who says, "Because the position is exempt and also because no law requires an employer to give employees vacation time, then the employer can require employees to answer the phone while on vacation. Moreover, the employer does not have to pay the employee additional wages or reimburse vacation time for the employee's doing so. The reader is discovering there are two types of vacations: those in which the employer says have a good time but be available to answer questions and handle urgent matters that may come up, and the rare type ... in which the employee can get away with being truly unreachable on vacation."

So basically, it's up to your company whether to offer you vacation time or not, and if they choose to offer it, they can put restrictions on it.

Legally speaking, that is.

Now, is it smart? Maybe, maybe not. It depends on a whole bunch of factors, like the nature of the work you do and whether the vacation was planned in advance or last-minute and when exactly you're taking the time off. (I've certainly told people before that the only way they could take a particular week they wanted was if they were willing to answer emergency calls because something important was happening that week.)

But assuming that it's planned out in advance and you negotiate the timing with your boss, the vast majority are jobs are ones where people should able to get away totally uninterrupted for a week or two. And smart employers will encourage that, because they should want people to return to work refreshed and recharged.

In any case, assuming that you're not springing this time off on them at the last minute and that haven't chosen an especially bad time to be away, talk to them about (a) what you'll do in advance to ensure your work is covered while you're away (if applicable) and (b) why uninterrupted vacation time matters.

And if that doesn't work, then you can always explain that you're going somewhere without reliable cell phone coverage and that you'll be difficult or impossible to reach most of the time.

Want to submit a question of your own? Send it to alison@askamanager.org.