First, anyone skipping out on their responsibilities shouldn’t be getting a sympathetic reaction (and, yeah, I know they always have stories about how it’s justified in their case - my dad spent a lot of time hanging out with other deadbeats but every time details came out, surprise, surprise, they were leaving out a lot).
Paying people under the table has a lot of potential liability for you and it almost always catches up with them. Especially now it’s just not viable to live off the grid (e.g. hoping you don’t get sick isn’t effective) and all this does is ensure that the amount they owe the IRS is unaffordable when the bill finally arrives, usually when their earning potential has gone down.