That's a bad idea in general. A paid day of work may be legally impossible for some candidates who are currently employed and have signed an agreement with their current employer regarding IP rights and/or conflict of interest.

The way I've seen it implemented is that companies just wire it via Paypal and don't think too hard about it.

Wait, I meant startups. So compliance? Probably not a thing.

It's not a compliance problem for the hiring company but potentially places the candidate in legal jeopardy.