A couple things:
If you really want to leave the cue ball as close as possible to the head, you can choose a BIH position close to the head string and side rail and shoot across the head string (out of the kitchen) at the opposite side rail with English to spin the CB back into the kitchen possibly get close to the head rail.
I'm sure Mr. Jewett could explain this better than I can, but I'll give it a try. Regarding the unsportsmanlike conduct concept related to the bad play behind the head string, it might be useful to read the lists of examples of UC that are listed in rule 6.16:
6.16 Unsportsmanlike Conduct
The normal penalty for unsportsmanlike conduct is the same as for a serious foul, but the referee may impose a penalty depending on his judgment of the conduct. Among other penalties possible are a warning; a standard-foul penalty, which will count as part of a three-foul sequence if applicable; a serious-foul penalty; loss of a rack, set or match; ejection from the competition possibly with forfeiture of all prizes, trophies and standings points.
Unsportsmanlike conduct is any intentional behavior that brings disrepute to the sport or which disrupts or changes the game to the extent that it cannot be played fairly. It includes
(a) distracting the opponent;
(b) changing the position of the balls in play other than by a shot;
(c) playing a shot by intentionally miscuing;
(d) continuing to play after a foul has been called or play has been suspended;
(e) practicing during a match;
(f) marking the table;
(g) delay of the game; and
(h) using equipment inappropriately.
In other words, bad play from behind the head string is not acceptable as an intentional foul and from what I've been reading in some of the posts, the term intentional foul is also part of the confusion. An example of an intentional foul is playing a safety shot where the CB barely moves and nothing drives the rail. This is acceptable and part of the game. What is not acceptable and not part of the game is to pick up the 13 ball and place it wherever you want. Yes, of course, it is an intentional foul because that was your intention. So I guess you can think of the phrase "intentional foul" as "acceptable intentional foul."
Hope this helps.