Well, I would liken intent to use a condom to a traditional bell curve.
Just because someone doesn't use one once, doesn't mean they always act that way, and vice versa.
I would say there is about 20% of the people who are truly mandatory condom use, they don't even flirt with the idea of not using one. No teasing play, no chance of it slipping in unsheathed.
Another 20% or so rarely use condoms if at all.
And the rest in the middle vary. Most of the time they use, but not always.