Shear strength of self-tapping screws fastening metal fence panel to metal post?

Help out a neophyte who is erecting a patio fence using 30" metal bar fence panels in five and ten foot lengths. The fence weighs about 15 pounds per linear foot. Would #14 steel self-tapping screws(I think this is the size), two on each end of the panel, support this weight adequately or would it be better to use 3/8" bolts. With either method, I had planned to use added support under the bottom rail. Self-tapping screws are attractive for their ease of use and fewer assembly steps needed. The posts will be 14 gauge steel 3 X 3's, so I will either drill into them with self-tapping screws or drill a 3/8" hole (through holes for straight runs of the fence and blind holes for the ends and corners).

You guys with the experience and knowledge tell me what's best. I certainly want it to be safe and well secured most of all. But what about the shear strength of self-tapping screws, can they handle this? Thanks for sharing your know-how with me.

In short, no. I would use the 3/8 bolts.

Maybe I'm thinking ovekill hear, but the problem with self tappers is that when you are setting them in they can easily stress the threads they make, and you don't know how much stress you've put on them because while you were drilling at full speed, the tap caught, self threaded, and locked the screw into place, usually that takes a fraction of a second, and unless you're in perfect control, you can easily stress the threads. once the threads are stressed they are easy to pull out. And you should never have to worry about sudden failure on a railing (afterall, what happens if a large person leans against a few years down the road). The advantage to a nut/bolt is that even though you may have to retighten them now and again, the nut has to come all the way off before the railing can fail. long before then I would hope somebody'd have noticed, and retightened.