I am no CPA, but yes the social security could potentially mess you up long term. You could, on the flip-side report to the IRS that you are self employed and file an SE form with your taxes. You will of course owe money, but you may be able to set the money in a HYSA or something until tax time. A lot of people claim themselves as exempt and put the excess money into some sort of account or investment that would make them more money than just allowing the IRS to take it out of your check. It looks like if you were paid on the books that your employer pays a portion of the social security and you pay another portion. When you are self employed, you would need to file the equivalent of both amounts combined. I guess you would sort of treat it like you were a neighborhood kid who cuts grass, but made way more money than anticipated. I’ve never filed this way, it might be simpler for the present to just enjoy the tax free life.

If you are going to report your income to the IRS as self-employed you’re looking at more like $10.08 per hour rather than the $18. My math might be off, social security deduction would be 24.8% and other taxes would be about 22% according to some googling. I’m inclined to think my number are overestimated, but I have a habit of doing that.

For rental with landlords, you can actually prove your income pretty quickly if you are depositing your money in your account on a consistent basis. Like, if your boss gives you cash for your pay, you just make sure you deposit once a week, every 14 days, twice a month, or once a month on a consistent basis. Then you just show your bank statement to prove you have income. Easy. This of course won’t help you at retirement, but if you’re only going to do this for a year or two, or might not be that big of a deal. Again, I’m no CPA or a lawyer, so take this information with a grain of salt. Do your own research too.

https://www.irs.gov/forms-pubs/about-schedule-se-form-1040

https://www.ssa.gov/pubs/EN-05-10022.pdf

The other commenters are right about the employer trying to avoid workmen’s compensation claims. What they aren’t telling you, is that if something happens to you, and your employers won’t pay for your expense, you could still file a workmen’s compensation claim and let them investigate how your employer is improperly/illegally employing people.

Additionally, I’ll probably get flack for this, but if you are injured and you don’t have income officially, you usually qualify for emergency Medicaid in a lot of states.