在Google Webmasters於2016年的這次直播中，John Mueller提到了：
We don't really care about underscore versus dashes. So that's something where I wouldn't bother setting up redirect for something like that. If the site is set up on one way, and using the other way would be nicer, obviously you could do that. But I don't think you'd see a significant kind of positive effect in search from that alone.
I mean, the thing to keep in mind there is, essentially, you're doing a site structure change if the URLs on your site. So we don't recognize that you're just, like, flipping out characters there. We see these are completely different URLs. And if you change your internal linking structure and the URLs that you're using on your website, then we kind of have to re-crawl and re-index a whole website to understand it again the context of the individual page. It's kind of the same if you go from, I don't know, from dot PHP to dot HTML or you remove the dot PHP completely. We run across completely new URLs. And we don't understand kind of intuitively this relationship between the old version and the new version. We just see these are new URLs. There are redirects there. The internal linking structure changed significantly. We have to kind of reevaluate the site. And that could result in, after some time, definitely seeing some fluctuations for where things kind of need to settle down. And in the long run, I think you'll see everything come back to the same place again. But it can definitely take, I don't know, a couple of weeks, maybe, to kind of settle down again.