I will still write 'use strict;' even if I do a 'use 5.012'. It's a little effort, and I'm not going to assume everyone will know that at some point in time use 5.xxx implied use strict, and that they know at which point in time that was.
Besides, writing "use 5.012;" without a "use strict;" runs the risk someone removes the "use 5.012;" (not unreasonable if there's nothing in the code that actually needs 5.012...), and then have it be without strict.
I never liked the idea that "use 5.XXX" implies subtle changed behaviour other than "without the mentioned version, it's unlikely to compile". I prefer "use 5.XXX" to mean one of "if you try to compile this with 5.YYY, where YYY < XXX, you'll fail" or "this code will trigger a bug in 5.YYY, which was fixed in 5.XXX". The implicite turning on of strict isn't such a change. Now it mean "if you try to run this with 5.YYY, I'm going to keep quiet if you screw up". Not what I expect of a helpful language.
I will only slap a "use 5.012;" label on my code if there's actually anything in my code that won't run on 5.010. So far, I've written next to no code that needs 5.012. I'm not going to artificially restrict my code to a certain version just so I don't have to type a few keystrokes (which I don't have to type in the first place - an editor macro does that for me).