Obviously meals and so forth as well. (And, assuming the law hasn't changed, US government employees have to pay for even a modest meal at a company's executive briefing center.)
OTOH, I've had 1099s for even very modest side-consulting revenue.
$600
Is it actually? I run a small business, and have trialled people a few times. I normally just transfer them the $x and report it as a business expense, same as you'd do with a contractor.
Maybe it's not technically 100% compliant, but I'd be incredibly surprised if the tax office kicked up a stink about something so petty.
(Then again, maybe it's just a "she'll be right mate" attitude that permeates even government departments here in Australia)
Depending on the potential employee's contracts and business rules, doing a side project for someone may or may not be 100% kosher.
If they don't have an ABN, they'll need to give you "Statement by a Supplier" [1], otherwise you're required to withhold tax at the top marginal rate.
[1] https://www.ato.gov.au/forms/statement-by-a-supplier-not-quo...
They're the ones giving take-home assignments.
Assuming this is legal at all according to current employment contracts, it's a huge pain for the new employer's payroll and more stuff to keep track for the employee's income tax.