It might be useful to do a summary of the theories about LEK: where she came from, why she changed her name, perhaps why she did some of the things she did. I've come up with a list of six of these theories, one or two of them admittedly implausible, but since the list is so short I went ahead & included them. Except for these few, all of them are equally likely, & only when we know more -- possibly more than we can ever learn -- will we know which one was the truth.
1. LEK was an illegal immigrant from Canada. In the 1980s, the border was a lot more porous than it is today, & there was nothing to prevent someone from Canada coming into the US to live any more than someone doing the same from Mexico. However, Congress passed a law (IIRC, PL-99-603 published in November 1986) that required all employers to provide proof of citizenship from all potential employees, which required illegal immigrants to either come clean -- or find another way to be a legal US citizen. Such as assuming the identity of a dead 2-year-old.
2. LEK escaped from a cult, the most often mentioned one being the FLSD, or some remnant of it. (Actually, this theory is mentioned so often, it could be considered theory "2a".) She lacked a birth certificate or other legal proof of being in the US, so she had to find another way to obtain legal proof she existed. And due to the nature of the cult, she made an effort to hide from its members out of fear.
One variant of it -- that LEK was an escapee from the Church of Scientology -- is not likely. People have left the CoS in droves for decades -- it has an amazing churn of membership -- & despite having a frighteningly effective intelligence section, the CoS doesn't go after former members, as long as they don't talk about the CoS. So there's no reason for LEK to hide were she a former CoS member.
3. LEK came from a commune -- as in a remnant of the 60's Counterculture -- that also failed to provide her an official birth certificate. These do exist, the one best known to me being the community of Takilma in Southern Oregon near Cave Junction. I suspect that other ones exist in Montana, Idaho, New Mexico & in other Western States -- at least into the 1980s.
4. LEK was hiding from someone; perhaps she witnessed a felony, or was involved as an accomplice, & fled for her safety. The theory that she was "hiding" depends on (a) her motivation for changing her name, & (b) her motivation for not wanting her marriage to Blake Ruff publicized. But both actions have other possible explanations, so I'm not convinced this theory is possible -- although I can't provide a definitive reason why this theory isn't the truth.
I think the fact that Agent Velling ran LEK's prints & image thru law enforcement databases & failed to get any hits proof that LEK wasn't wanted for any crimes. While it's possible she may have committed one or more felonies, if so she escaped detection for them & had no need to change her identity. And arguing that she committed a felony, was not suspected of it but did not know this, yet went into hiding anyway is wandering off into Silly Conspiracy Theory Land. (Or as others in this forum used to call it, "Days of Our Mustard".)
5. LEK changed her name to "start her life over" -- as a break from her past. There are some signs in what is known of her life that this may be the case, points where she tried to "paper over" her past, to provide a fictional story so she need not tell the truth: her fabricated Letter of Recommendation from a boss in Thailand, & the entry in her resume for the years July 1992-January 1998. (She could have simply stated she graduated from college in December 1997, but it was important to her to account for those 5 & ahalf years.)
I admit I favor this theory because I know of several women who have changed their first names for this reason. Especially because a number of thee women I know had mental issues. But one could consider that the theory LEK changed her name to start over because of mental issues she was not successfully dealing with a subset of this theory -- say "5a".
6. LEK was living under a fake name because she was a sleeper agent for the KGB or another foreign power -- the theory the Ruffs are credited for. (But I don't know just how seriously they believed this theory; since LEK seemed to have dropped out of the blue sky, they may have simply joked about it.) This the one theory we safely dismiss. Had there been any possibility this might be true about LEK, Agent Velling would never have asked for help from the general public: long before he reached that point, I'm certain that someone from the US intelligence community would have taken over his investigation, & all that we would then have is a dead thread on Websleuth about a woman whose name could not be mentioned.
So have there been any other theories about LEK that I overlooked in this summary? Serious ones, please: no need to argue she was a stranded passenger from some extraterrestrial space ship, or any other theory just as silly.