I've worked at two employers who used the contractor loophole. At the first one, the length of the contract and extensions were never mentioned to me ever. The second one constantly played games with extension. At one point I was set to have my final week of employment, only for them to extend it over the weekend.

I've been in the contractor shoes for way longer than I should have (which is zero), So as a hardfast rule, "expect your contract to end on its end date" simply doesn't hold up. Corps like to play games with it, and leave employees out of the loop.