To my knowledge, I've never had a log entry I didn't in some sense call for.
If you send RR73 or 73, then if you have the normal set up, it prompts you to log. Most long time users hardly think about it and might not even remember responding. I know I have sometimes forgotten in the "heat" of "battle" that I have, in fact, logged someone.
To get two of these, simply be in a situation where you repeat the 73 or RR73.
Also, you can hit the 'log' button manually and if you again confirm without much thought, you can log a station you didn't work. Not common, to be sure, but if one is busy trying to outsmart and FT8 pileup on a 3B7M (for instance) not impossible, either.