I am opposed to internal control locks in all but the most dire circumstances. They will allow flight controls to be forced through the enitre control mechanism against the cockpit control lock. It is a certainty that fatal loss of control accidents have occured because of hidden control system damage from cockpit control lock use. THIS is the serious safety of flight risk the pilot CANNOT detect during a walk around. Danger danger! I have found myself airborne in a 182 with hidden aileron damage, which was not detectable during the walk around.
in an older Cessna POH, Cessna recommends that each tiedown point be able to withstand a 700 pound pull. This kinda makes sense, in that your average GA plane is 1200 to 1800 pounds empty, and like to fly at 40MPH, so at that 40MPH wind will create around 700 pounds lift per wing. Story:
back in the day, I was the custodian of a 172, which shared the apron with a Seabee. Each were tied to a few hundred pounds of concrete slabs. A paniced phone call from the non pilot farmer very early one morning; the two planes had been blown into each other over night. I was respnsible for the 172. I rushed to the airfield. The 172 was exactly as I had left it. The Seabee (a rather heavy, unaerodynamic plane, had bumbled it's way a few hundred feet across the apron. It was at rest with it's wing shadowing the 172's, but having not contacted, and those concrete slabs on the rope were now swinging off the ground, suspended by the tiedown rope, still tied to the Seabee wing, but now passing over the aileron of the 172. I bent back out that curled train aileron edge. I moved the 172 away, for it's safety, the Seabee was badly damaged. i learned about tying down from that.
I have seen planes lying on their backs, with ropes and anchors still attached.
There is something to parking taildraggers tail down into the wind, but I would rather tie them down really well, into the wind. If I have to leave a taildragger untied, then I will try to tail it into the wind.
I have made effective exteral control locks for both of my planes. I do not apply cockpit control locks. I do like the Cessna Caravan external rudder lock - Cessna hsa learned!