I go back fairly far with straight pool, to the mid 60s rule books. As far as I can tell, as long as you strike the cue ball with the proper part of you cue tip, a double hit is not unsportsmanlike conduct, whether the cue ball ends up in the jaws of a pocket, or not. It is though, a foul, maybe intentional, or maybe not.
The lesson is, when you commit the first foul (whether intentional or not), you may have a difficult situation on your hands, because you're the first one to foul. You probably are the one who is going to have to disturb the rack to get the game going again, or you suffer the 15 ball penalty. Own up to it, when you are the first to foul.
You did notice, didn't you, that I said "with the proper part of the cue tip." I note this because in the 2000 Straight Pool tournament as the Roseland Ballroom in New York, Efren Reyes tried an intentional foul on Dallas West by just poking the cue ball with the ferrule-side of his cue. They debated a while, and Mike Shamos was about the only one to note that was unsportsmanlike conduct. If Efren had done it with the front (proper) part of the cue tip, he would have been fine, just an intentional foul, but no unsportsmanlike conduct.
Bottom line, I don't see the problem with where you put the cue ball on an intentional foul, as long as you attempt the shot with the proper, front of the cue tip, possible double hit or not. It's still a foul, as the player intended. The player with the first foul has to extricate himself out of the situation. It's basically how the game's always been played. If you, as the second fouler, has the skill to put the cue ball in the jaws of any pocket, more power to you. After all, you were not the first to foul.
All the best,
WW