Here's a hard-and-fast rule: Don't give your Social Security number to anyone unless it's absolutely necessary.
More than 12 million Americans fell victim to identity theft last year, according to Javelin Strategy & Research. Losses topped $21 billion, with the costliest data breaches involving fraudsters gaining access to people's Social Security numbers.
With all that in mind, it's hard to imagine that any business nowadays would ask consumers to part with their Social Security number except for the most important of reasons.
Unless that business is a cable, satellite or phone company.
I wrote last week about a Time Warner Cable customer who decided to join the growing number of people cutting the cord from costly pay-TV subscriptions. He blamed the continuing spat between Time Warner and CBS.
Michael Bell, 57, was similarly fed up with Time Warner Cable and CBS bickering over which should get more money. But instead of cutting the cord, he decided to switch from cable to DirecTV's satellite service.
Bell told me he called DirecTV after Time Warner Cable dropped CBS and Showtime programming Aug. 2 and asked a service rep for some price quotes. He wanted to know how much for TV service, how much for Internet and how much for both.
You'd think that wouldn't be so hard to process.
The DirecTV rep began by asking for Bell's name, his phone number, his address and whether he lived in a house or a condo.
"That all seemed like reasonable stuff," he recalled. "They needed to know if I could put a dish on my home."
Then the rep asked whether Bell owned or rented his Simi Valley house.
"That stopped me," Bell said. "Why should he care? I told him I just wanted a price quote. He said we'd get to that. And then he asked for my Social Security number."
Bell said thanks but no thanks, and promptly hung up.
His instincts were correct. A request for a Social Security number should be seen as a red flag in almost all circumstances.
Robert Mercer, a DirecTV spokesman, told me the company has a good reason for wanting people's Social Security numbers.
He said DirecTV spends an average of $890 installing a dish on each new customer's roof and providing other equipment and incentives, and thus needs to get a sense of people's finances.
"We've been scrupulously doing credit checks for years," he said. "We want to ensure that we're bringing on good-quality, creditworthy customers who can pay their bills."
Mercer noted that if you don't want to provide your Social Security number, you can pay a fee of up to $300 to mitigate DirecTV's risk that you'll be a satellite deadbeat. The fee is returned over time in the form of a $5 monthly credit, he said.
DirecTV isn't alone in claiming to be financially picky about who should get its service. Comcast, AT&T and Verizon also require a Social Security number upfront or will make you pay a fee if you'd rather protect your privacy.