But besides the practical aspects there is also a moral angle. Two adults should be able to come to a wage agreement without governmental interference.
If an otherwise unemployable pensioner wants to get out of the house and make a few bucks - why should the government have the power to prevent him from doing this? And if a non skilled high school drop out is willing to work for a low wage to get some experience - why should the government be able to stop him?
I recently met some one who graduated with a degree in Industrial Engineering over 40 years ago. He told me that his first job was for a building company that didn't understand how he could help them. He offered to work for free as he wanted to get experience in that field. He told me that after the first year he had one of the highest paid positions in the company.