Usually the only thing that can be done during job verification is:

- did they work there?

- can they be rehired?

If the second is a "no" it usually isn't good news (usually, that only happens when you're fired 'for cause', at least in the US).

So, it isn't as pretty as an offer as you'd think.

If somebody started mere days ago, they can simply omit this job from their CV entirely and nobody would notice the gap.