Fellow Virginia Tech alumnus here. "VA Tech" is perfectly legible and unambiguous. "VT scientists" is straightforward to Americans, but not everyone in the world will know what "VT" is in this context. It could be Vermont scientists, or who knows what else.

Incidentally, the author is the wife of physicist Sean Carroll. She certainly knows how to abbreviate Virginia Tech, but Ars Technica's editors will want to influence the title to appeal to a global audience.

"VA Tech" is a reasonable balance between writing something unambiguous for a global audience, but short enough to be interesting. Nobody's going to be interested in an article titled "Virginia Polytechnic Institute & State University scientists build a better fog harp."

Of course, you still need to read the article itself to find out what the heck is a "fog harp," and why we need a better one.