Prevent starting features machine name starting with numeric

I ran across a newbie stumbling block I wanted to call to your attention.

I had been trying to create a Feature that would define a basic set of Image Styles for a 16 column grid. I exported the Feature with the Image Styles component and a long list of image presets for different sizes (with a long list, defining all those styles is time-consuming).

But when I tried to install the new Feature on another site, it didn't even show up in the Features or Modules list. I checked all my settings and exported the Feature again, but still no luck. So I checked the files against another Feature set I had exported and installed successfully, and couldn't find anything wrong.

Then it dawned on me that I had named the Feature "16_col_grid_imagestyles" and maybe the numeric characters could be the problem. Sure enough, when I exported again with a new name "grid_sixteen_imagestyles" The Feature showed up in the list and loaded correctly.

I didn't realize that you can't use numeric characters in the name like that. So for the sake of other newbies, I wonder if you might add an instruction under the new Feature Name field that says "alpha characters only". Or, if it's not too difficult, maybe that field be set to restrict names to allowed characters only so that it won't save without a proper name.