If you want to do that by way of an open source portfolio, sure. But not everyone has open source contributions, so then I would need some other process for acquiring a work sample.

I have seen many people here say you should hire people on a contract basis for a few days/a week. I don't know what it's like doing that in the US, but for the UK market that sounds like a ton of administrative overhead for both parties to take on in order to establish if they are even a good fit.