Can giants break away from average sized figures without having to roll?

At the venue I played at recently, that was the ruling based on the rule book declaration that giants ignore placticity. The guys at that venue are great, but I think that ruling may be incorrect. I thought the ignoring of placticity just made break away a normal action.

What is correct in this regards?

Giants successfully break away on a roll of 3-6, instead of the normal 4-6, regardless of whether the opposing figure has Plasticity or not.