Dangerous because HR people and recruiters tend to switch companies and even industries constantly, and because any given company is obligated to keep your resume on file for a certain number of years -- inclusive of any remarks made by HR or the hiring manager about it. If you want to risk being essentially blacklisted for lying on your resume, I guess your risk tolerance is higher than mine.

I get the argument about the risk's being mitigated over time by the downside of being unemployed for 6+n months. Mathematically, sure, this starts making sense after awhile. But it seems much less risky just to invent (or hey, attempt to start) a fictitious company than to lie about having been employed by a real one, defunct or otherwise.