The Get To Work question you're all tired of answering.

The only time I've ever run into aliens in my games (outside of when playing the Science career or adding them into my game myself) is when I've stumbled upon alien night at the bar. Other then that I've on occasion had a non-science sim get abducted but it's very rare.

I haven't come across a true random in-the-wild hidden alien in my words in a really long time...like YEARS...sometimes I wonder if the game even actually does spawn them that way anymore if you don't trigger it into happening some other way.