Would you really gamble your hard-earned savings on the hope that inflation will remain virtually nonexistent for the next 10 years? How about 30?If you think that's ridiculous, don't laugh. Millions of Americans are taking precisely that high-risk bet. And many of them don't even know it. You may be among them. Why? Because this is the quiet and dangerous wager now being made by anyone who invests in regular, long-term U.S. government bonds. That includes those who invest in mutual funds that specialize in such bonds, like the ( VUSTX) Vanguard Long-Term Treasury Fund (VUSTX). This follows a slump in the yield, or interest rate, on these bonds recently. By Friday, even after a small bounce, the yield on the benchmark 10-year Treasury closed at a paltry 4.64%. That's the compound annual interest rate you'll get if you lend money to Uncle Sam for 10 years. If you want to see how crazy that is, have a look at the yield on another asset class: The special group of inflation-protected government bonds known as TIPS, or Treasury Inflation-Protected Securities. And 10-Year TIPS, as of Friday, were yielding 2.32% in real, post-inflation terms. That's what you get back on top of any increase in the consumer price index each year. The net result? The only reason you'd buy the mainstream Treasuries instead would be if you thought consumer inflation over the next 10 years will work out as less than the difference between the two yields. In other words, 2.3% a year or less. Yet that's what legions of investors are doing.