This may be a strange question and I may have some misunderstandings.
In my experience it's not unusual for a contractor to be doing the same work as a regular employee. For example if a firm needs extra people during a busy time they hire contractors on for a short period of time. The contractor would likely use the same company equipment. They would work off the same computers, printer and stationary etc. as everyone else in the office.
It's a common misconception that a written contract determines whether an individual is a contractor or employee, but this is not the case (at least in Canada, and I thought the US too). The distinction between contractor vs employee is actually done by a set of tests.
Since contractors often do the same work (and in the same way) as regular employees do, does that mean its common for businesses to be "pulling a fast one" when they hire people as contractors?