There's a reason why car companies haven't been using line locks and other hydraulic part for parking breaks.
Your break system will always be sitting under pressure, putting more wear and tear on your seals.
There is a possibility that it can bleed off, sending a rig a rollin.
The Jamar line locks are known for bleeding off if used as a parking break and left for a while, There supposed to be used for short holds.
My 0.2
Amilla