This is a good fear to have. There are still situations where a space will fuck things up.
source: I am building a html site on neocities. I don’t know if it’s Neocities or my ftp client or something else, but, if I ever forget and upload a html file, or any file, with a space in its name? Not only does that file not work on the website, but it can’t even be deleted. It’s just forever stuck in my directory being a useless broken thing, as if the space is some kind of hole in its heart that can never quite kill it.