If you watch television, you have probably seen Ed McMahon, Dick Van Dyke, Danny Thomas, Art Linkletter or some other television personality trying to sell life insurance policies for people older than 50.

Thomas, for example, tells us that the policies he endorses, which guarantee acceptance to anyone, offer "top-notch coverage" and "provide a perfect opportunity to increase your family's security."

But most people older than 50 would be better off putting their money in the bank -- or even in a mattress. Here's why:

Most mail-order policies offer no benefits for the first two years, no benefits after age 79 and sharply declining benefits in between.

For example, for $297 a year a man who has just turned 57 can buy $8,750 in life insurance from the company Danny Thomas endorses. If the man dies when he is 57 or 58, his beneficiary gets nothing, because of the two-year exclusion period. If he dies at 59, his beneficiary gets $8,750 -- in which case the insurance would be a good value, since he paid only $891.

But if he lives until 70, the benefits under the policy drop to $3,250, after he has paid $297 for each of the last 15 years, or a total of $4,455 -- which would equal $6,410 had he put it in a savings account earning 5 percent interest. If he lives until 80, his beneficiary would get nothing -- after he has paid $7,425 in premiums and has forgone $6,744 in interest.

Better insurance at a much lower price is available. Most mail-order policies offer so-called "decreasing term" insurance, under which the premium stays the same but the benefits decrease over time -- which the companies seldom mention in their television ads.

Most older people do not need life insurance, which is to provide for the insured's dependents if he or she dies prematurely, not at or near the end of a normal life span. People who want to provide for their families after they retire will have more to give them if they save or invest their money.

Why do celebrities endorse these policies? The obvious answer is: for the money.

It is puzzling how these ads can remain on the air. The Federal Trade Commission normally can prosecute "unfair or deceptive" advertising. Insurance companies, however, are exempt from FTC scrutiny. Bob Hunter is president and Jay Angoff is counsel of the National Insurance Consumer Organization in Alexandria