I agree it is not a bad idea to confirm previous employment. It still does not prevent the case you mention, but it might help.

I just wanted to add to anyone: make sure you actually understand who was the employer and give an opportunity to address the potential lie.

Sometimes people (in a rush to read the cv) assume that a contract position, for instance, was a permanent role and similar mistakes (even when clearly specified in the cv) and these checks might make people drop out of the process unfairly, without recourse.