Absolutely.
In one test sugar pills were found to work 40% as well as Morphine against post surgical severe pain.
Placebo effect is VERY real (although it sometimes goes by other names, like "expectation bias").
The only way to be sure about anything subtle is by a real double-blind test.
On the one hand, turning your outlets upside down at least doesn't cost anything, and causes no harm
(as long as you're careful and don't mess up the wires), so there isn't a lot of incentive to test and verify whether it's real or not.
But, on the other hand, I always like to verify claims that seem contrary to science very thoroughly to avoid
"promoting superstition and magical thinking".
(In other words, using a placebo to help someone with pain from an injury is indeed helpful, BUT it does encourage them
to believe that a different placebo might cure them of, maybe, an infection. In that case, if they take the placebo
instead of a real antibiotic, since bacteria don't respond to placebos especially well, the results could be very bad.)
The placebo effect is real. There's lots of medical evidence even.