Retouching on Sci-Fi and Literary agents

As a follow up to my recent blog on Sci-Fi and the mainstream, I thought I'd add some examples of books that I've enjoyed that were not found in the Sci-Fi section of the bookstore, obviously got published, but that have elements of them that any Crime Thriller reader would presumably have a hard time swallowing.

The Nosferatu scroll by James Becker doesn't have a full on vampires turning into a bat or being staked through the heart or anything, but it deals with the idea of Vampires being real and immortal, and more than weird cultists drinking the blood of the friends in sexual rituals - does that make it sci-fi?

The Chase/Wilde series by Andy McDermott, has a continuing plot point of Earth energy as a potential clean energy source or as a weapon. Only certain people can sense it and channel it, and Excalibur was revealed in one of his books to be a direct conductor for that energy due to the material it was constructed from. Does this make his books sci-fi?

The Seven Ancient Wonders, Six Sacred Stones, and Five Greatest Warriors by Matthew Reilly deal with cosmological events and solar catastrophes that can only be averted by machines built thousands of years ago that magically fix the problem if you've set up all the right pieces. I was happy to accept it just to be so without the physics explained, and loved the concept - but is this therefore sci-fi? I mean, it's not like modern scientists invented something to prevent a huge solar flare; it was unknown builders at the dawn of civilisation, which surely is a stretch - but it's in the Thriller section. Oh, and one of the characters has also invented a fully functional bionic arm, and things called warblers than create a bullet deflecting shield of sorts. It's brilliant, but it's not current tech or in the realms of.

So how far can one go and still have their work considered suitable for agents that deal in the Thriller genre but not Sci-Fi? Obviously every agency is going to have a personal opinion on what is and isn't "too fantastic". But with so many sub-genres popping up you would have thought there would be more leeway.