This is the logical route, and probably what should've been done to start. As it stands though this would generally result in most locks activating at 150 skill at most, and would cause rioting in the streets.
What I think would be a better solution and more fair would be if locks activated at the same skill as the person whom the lock was borrowed from.
Since it seems there is a workaround available for demons on locked weapons, I would recommend taking this route until such a time as there is a new system for lock activation implemented. I appreciate the frustration felt with the hard ceiling that currently exists with locks but until they're reviewed we won't be making any drastic changes. In other words, keep belting out ideas for how we might tackle the problems players are facing with lock activation and we'll have a more complete data set to work with when we begin reviewing them.
Just don't expect the lock limit's hard cap to be pushed to 300 and left alone to be the fix.