I saw a film where in two separate scenes the characters seemed to use the "imperative-prohibition" to invite the opposite action:
1.In one scene a father after explaining something to his son appeared to ask his son if he could understand what he had explained:
「わかるな」?
It was as if he had said: 「[おれのいうこと]、分かりませんか」?
2.In another scene a woman invited a child to sit on a chair that she was pointing at:
「すわんな」
As if she had said: 「座りませんか」
In both cases I am sure I have quoted the subtitles correctly but is this really the imperative prohibition or have I missed something?