Actually, it's worse than that - theoretically, they should be doing an F-test, but those are essentially useless[0] except as exercises for unfortunate undergraduates.

This gets into the flaws with hypothesis testing (and p-values) as a tool altogether, though. And while I would love to see the natural sciences eschew these rather rudimentary heuristics in favor of the more sophisticated modeling tools that we already have, I'm not holding my breath on that happening anytime soon.

[0] http://andrewgelman.com/2009/05/18/noooooooooooooo/