You should use chock when parking a trailer without spring brakes because
a) If the air supply leaks away, there will be no brakes
b) You don't want the trailer rolling down a hill
c) Some states require chocking of trailer wheels
Answer: a) If the air supply leaks away, there will be no brakes
If the answers is incorrect or not given, you can answer the above question in the comment box. If the answers is incorrect or not given, you can answer the above question in the comment box.