In the first instance...absolutely legal..............and remember this is not throwing to an unoccupied base....I have wanted this rule should rewritten for clarity as many coaches and umpires only read the intial part of the rule....."you may not throw to an unoccupied base" part without reading the rest of the line that says with the exception of making a play.....
had they started the rule with the statement I feel there would be less confusion....
"With the exception of making a play, you may not throw to an unoccupied base....."
He is making a play.......so no unoccupied base applies... And in HS, it doesn't even have to be a play. A throw or fake throw to drive back a runner is legal, even if the runner heads back .
In pro rules however, in the second instance, there has to be a real attempt.....