Is Snuck Not a Word?

I recently noticed that my Internet spell check didn't have the word "snuck" in it.  As I type this, snuck stands with a squiggly red line under it.  I googled it and found that indeed it is not the proper past participle of sneak.  One would more properly say, "I sneaked into the room," or, "I had sneaked into the room," instead of, "I snuck into the room," or, "I had snuck into the room".  However, as I found here, the usage of snuck instead of sneak has become so pervasive over the past 20 or so years that it can no longer be said that snuck is non-standard usage of the verb to sneak.  So there.