Anyone who's never tried using a pressure cooker before, or even thinks that they're dangerous without even learning more about them, they'll quickly assume that the wrong things about them are about to happen. And so, one automatically assumes that the worst is going to happen. Their #1 fear above all else, believe it or not, is that it might blow up during use.
But when used properly, and according to the manufacturer's instructions, they are just about as safe as an ordinary pot. I still have YET to hear about one having blown up. Because there are built-in safety features that help preclude that mishap from ever happening.
They're met with very strict manufacturing safety standards and comply with Underwriter's Laboratories (their 2-letter logo is stamped on these and most other consumer products for home use), meaning that they are very safe to use and meet or exceed all safety requirements set forth by the U.S. Gov't. The only time that they would ever become dangerous to use is if the owner or consumer messes up in some way and puts himself or herself & others in harm's way. This is why very strict instructions are given and should be followed with each one.
Respect the unit and the use of one, and it'll give you many, many, many years of safe, trouble-free reliable and enjoyable operation. Replace the gaskets, handles and other parts when they begin to crack or wear out (I've done that with one of mine, I've replaced the gasket and handles, and it still works like new), and you'll be helping the unit maintain its reliable trouble-free & safe qualities.
In other words, treat it right, and it'll be your friend for life. Just make sure that you "dot the i's and cross the t's". That's a true guarantee!