1/3 taxes on gross sales? That would be a 50% tax rate on the net revenue.
It really depends upon the amount of business being done. If there is a home office, and a small amount of sales, that could offset all the income and there would be zero taxes. I can claim $8,000 per year for my home office, so my first $8,000 net is tax free. Part-timers might be happy with that. (Also, if an economical car is used, the standard mileage cost allowed by the IRS is much more than the actual cost, so some additional income can be shielded from taxes).
Also, the cost of their equipment is going to offset income, so if they don't do much work, even without a home office deduction, they are not going to be paying any taxes.
These people already have their drones and the money has been spent. $90 to them at this point is free and clear. Is it better they don't do the work and be $90 poorer?