That's not a loophole that's in the plan. But the plan's a non-starter. It will effectively reduce the tax rate to a total of 15% for everyone who has the ability to start an LLC and have their compensation paid to that LLC. Already every doctor, lawyer, and other highly paid professional will instantly go from 39.6% to 15% effective tax rate on their income. Massive loss of revenue right there. Then every employee who makes more than about $50K a year forms an LLC and becomes a contractor to their employer and their personal tax rate effectively drops to 15%, it's a no brainer. As does every small business. You decimate more than half the tax base within a couple years by more than half. Since we're still waiting for those Bush tax cuts to pay for themselves, we end up with a massively increasing deficit or we make massive cuts the military, which is responsible for 57% of discretionary spending.
There are still a few people in congress who can do basic math, and ostensibly some who care about the budget deficit. Can't see how they can possibly do anything but laugh at this "plan".