If you chock correctly, I am of the opinion that one side is ok.
The problem I see is that people just kick a chock under the low side of the wheel and call it good. In reality you want to chock the front and back of the tire, and in a manner that "cradles" the tire.
To do this you need to use the TV to pull (or push) the trailer slightly up a chock and slip another chock in on the other side. This will capture the tire and put pressure on both chocks helping to ensure the trailer cant roll in either direction.