Right--it's not that it's a bad per se, and the lower you can get the temp the better off you're likely to be. Is it ideal? No, because as I said before, the longer you let the wort sit without pitching, the more likelihood (even if it's still low) that something besides your yeast will take up residence. But it's probably a manageable risk, assuming that you sanitize well and follow good procedures. Not something I would want to do all the time, but if it was between that and not brewing at all, I'd probably choose to go ahead and do it.