(image from CBS web site)
The anwer in many cases is YES. The article below gives good advise to the consumer. Don't be misled by the headline. Be sure to read the fine print!
April 11, 2007
Why It Doesn't Pay To Buy Travel Insurance
You're Probably Already Covered ... And You May Not Even Know It
“It may make sense to buy additional travel insurance if your health is an issue and you are traveling overseas. Some health insurance policies, such as Medicare, won't cover you abroad. Before you buy, check your homeowners and other policies [i.e. credit cards] to avoid any overlapping coverage. These policies may already provide adequate protection. Avoid purchasing policies through tour operators or cruise lines. If they go bankrupt, you could be out of luck. Instead, purchase through a third-party insurer … Bear in mind that not all credit cards offer protection, and that some are better than others.”
It is very good advise to check what coverage is provided by your credit cards (you have to use the credit card to pay for the trip for it to be covered) and /or your homeowners insurance policy. Will they cover you if you loose your passport on the way to the airport and are denied boarding for your non-refundable vacation in South Africa? Good travel insurance will.
For a cheap domestic ticket that can be reissued for a fee-you probably don’t need insurance, but for that tour of Europe or Asia be sure to purchase adequate coverage-just in case. And if you or a family member have a pre-existing medical condition make sure it is covered by the insurance you choose.