This time of year is a pain in the nadgers for releasing tie downs. Never ceases to amaze me how complicated people think these knots have to be!!! Anyhoo, whenever the tie down is stuck due to ice, chances are so is the aircraft and a judicial application of de ice spray/fluid and a well placed screwdriver gets the job done.
Just dont get me started on people who think that the oil cap must be gorilla-ed on with and industrial torque wrench.