Grandmothers have always advised not to count your chickens until they hatch. In today’s economy, the wise among us have a new pearl of wisdom: don’t assume that you have a job just because you received a job offer.

Especially in industries that are restructuring, the risk is real that an employer may be forced to rescind a job offer, particularly to a mid-level manager or executive who may have had an agreement in hand for months, experts warn. With corporate belt-tightening taking place on a regular basis, the next job axed could very well be the one that was offered to you.

“There is not much anyone can do in that situation,” says interview coach Carole Martin, a Redwood, Calif.-based human resource expert and author who runs the Web site InterviewCoach.com.

In most states, employment is considered “at-will.” That means an employer can terminate employment with even a prospective employee for any reason that is not discriminatory and that does not violate public policy.

Mimi Moore, an employment attorney in the Chicago office of Bryan Cave L.L.P. , says suing an employer for damages in the case of a rescinded job offer would not be advisable.

“It's not something I would advise employees to do,” she says.

Even in strong economic times, employers have the right to rescind job offers for a number of reasons: unsatisfactory results of a drug test or credit check, poor evaluations during a reference check or failure on the part of the applicant to fulfill all requirements, such as taking drug tests and signing all agreements.

Be sure to ask a company exactly why it rescinded the offer, Martin says. If you remain interested in the position, use the opportunity to resell yourself. If the company reneged for financial reasons, better times could put them back in hiring mode. “Make sure to express an interest” so you will be considered for a job down the road, she says.

Good employers understand the ramifications of rescinding an offer and might help you look for another job or offer some sort of compensation for expenses that you may have incurred – moving, for example. If you quit your job to start the new one, you may have to return to your first employer and ask about the possibility of returning. This is why it’s never a good idea to burn any bridges, coaches say.

The good news is that recent college graduates may see fewer cases of revoked job offers than grads have in previous years, according to Steven Rothberg, president of Adguide Publications, Minneapolis, and founder of CollegeRecruiter.com.

Although the economy is struggling and many people are being laid off or are unable to move into better positions, most organizations hiring recent graduates are reporting that they’re hiring about as many this year as last year; some are even recruiting more. And they’re not changing their minds prior to the arrival of their entry-level employees.

In the 2001-03 recession, Rothberg says, many corporations rescinded offers to college students and recent graduates, and later suffered for it.

“Those organizations… became pariahs on campus for years afterwards,” Rothberg claims. “They had huge holes in their employment ranks as a result of not hiring as many people as they should have in 2001-03 and then not being able to hire the quality they needed in the years afterwards.”

Job seekers still awaiting an offer can try to protect themselves by following some of the following tips:

Ask many questions about the position to determine if it’s a new one or one vulnerable to cuts.

Research to see if the company has a history of revoking job offers.

See if you can receive a bonus to which you’re entitled even if the offer is pulled.

Determine if the company can be billed directly for any relocation costs.

Ask for all company policy manuals that may describe circumstances that can lead a company to withdraw an offer.

Continue to pursue other opportunities until you’ve started your new job.