Likewise, I think this would be the most sensible approach. Some people want to die with their coins. 

>By leaving quantum vulnerable funds available to spend, the same set of users who would otherwise have funds frozen are likely to see them stolen.

That's really the argument for me. Quantum vulnerable funds are gone, they're going to get scooped. Either switch to quantum encryption when it becomes available, or lose your coins. I'd prefer them getting locked > getting "mined"