One of the great things about entrepreneurs is that they're constantly spotting problems and solving them. You burn your hand on your coffee cup, they come up with a java jacket. You need shades that go from indoors to outdoors and they, um, invent Transitions lenses.

The point is that entrepreneurs see opportunity where others don't. But is there a line between taking advantage of an opportunity and being an opportunist?

To wit: the New York Times' Style Section ran a story today about Lindi Skin, a line of products specifically for cancer patients whose skin suffers blotchiness and rashes because of medication, radiation, and chemo.

Here's the problem: there's no proof that this line—or any of the others currently on the market—actually do anything. And they're sold at expensive, department store prices. Of course, the same is true a myriad of other skin products that are sold to women to fix everything from dark circles to wrinkles. But some doctors say that going after cancer patients is what makes such brands particularly shady (via the Times):

"They're marketing to a vulnerable population," says one doctor. "Cancer patients go through so many body image concerns and changes. They get scars. Their skin changes from radiation. Sometimes the chemotherapy causes rashes. Their hair can fall out. They're going to try anything to look and feel better."

In fairness to Lindi Skin, the owner of that company says she came up with the idea after two close friends had bouts with cancer. And just because a person has cancer doesn't mean that they can make decisions for themselves or do their own research about the products they buy. But if, as some doctors say, it doesn't work much better than $5 drug store balm and isn't backed by any scientific studies—doesn't that feel just a little bit smarmy?

But I want to hear what you think. Are these entrepreneurs taking advantage of a bad situation or just capitalizing on a good opportunity?