I'm not expecting anyone to turn getfoobar into getf_oobar, no. But (1) there are cases where people might disagree about whether something is one word or two (

I'm not expecting anyone to turn getfoobar into getf_oobar, no. But (1) there are cases where people might disagree about whether something is one word or two (do you want to bet no one has written "white_space" where you wrote "whitespace"?) and (2) there are weird cases where the same string of letters can be split into words (or sufficiently word-like pieces) in multiple ways. I don't have a plausible example of #2 in mind. Maybe there aren't any. (There are definitely lots of things that break into words in multiple ways, of course, but maybe there aren't any that make plausible identifier names more than one way. Though for what it's worth I bet there are.) And in any given case you can check, given a few seconds' thought, that there aren't other possibilities. But that little extra cognitive load is a bigger deal than it sounds like -- it's a distraction from other things -- and if you don't do the check then you'll never know whether your search operation actually found everything it should have. So you can check by eye every time. Or you can write the ugly regexp every time. Or you can just accept that what ought to be a perfectly simple operation isn't quite right and might invisibly go wrong some time. That's not a set of options I like.