Not just a theory.
If you own something (a stock, I mean) that you don't love, sell it. The S&P 500 has gone up, almost in a straight line, 21% in two weeks. Taking some gains. or getting your house in order even if there are losses in some cases, makes sense.
Even if all the government silver bullets hit home, there will be another selloff that you will want to take advantage of. Gold will not be the best performing asset class forever.