Honestly, biometrics are terrible for authorization. They're more of a username than a password and we shouldn't use them like passwords. The same is truth for facial recognition algorithms, no matter how advanced.
They're so damn convenient, though. I trust the fingerprint scanner on my phone and my laptop, but there are definitely bad scanners out there.
I don't want my password to be something I leave behind on everything I touch, which the police have because I was arrested once, which can be ascertained from high quality photos, and which I can't ever change once stolen.
I've tried unlocking my laptop's scanner with my other hand and I've asked other people to put their finger on it to see if it does some kind of weird matching based on finger type. No problems so far. It even works across both Windows and Linux if I use the right Windows reboot incantations.
Since there is nothing genetic about fingerprints, I'd personally consider your daughter's laptop to be defective if you're able to unlock it. A critical part of the laptop's security mechanisms is clearly broken and should be looked at. I can't find many other stories about Dell specifically so this may be a specific unit or product line that's broken.
You may even have something to gain by reporting it; I don't know if Dell or their manufacturers do bug bounties, but this definitely sounds like something that should be accepted in such a program. Even if they don't, writing a short blog about it with the brand, model, and model of the fingerprint reader might get the press rolling, forcing Dell to take action. This is simply unacceptable.
> Since there is nothing genetic about fingerprints
While it's true that even identical twins don't have the same fingerprints [1], it's not true that there are no genetic factors in the general shape of fingerprints [2]. I agree that it's unacceptable if a fingerprint reader isn't good enough to distinguish identical twins based on the differences in fingerprints though, as those should be the most similar fingerprints possible, essentially setting a floor on the minimum uniqueness in the problem.
It seems like they would use identical twin derived validation data sets to ensure this.
They're so damn convenient, though. I trust the fingerprint scanner on my phone and my laptop, but there are definitely bad scanners out there.