Life doesn't allow me much time on chat forums, so this feels like a late response....
I've probably used the IDFK two or three times without a caution. I take the point of accuracy of law, but at my level I consider my job is to allow 22 people (plus subs) to enjoy a Saturday afternoon of football, played in such a way as they are safe and leave the pitch without injuries caused by the referee losing control in law. If this means that I interpret to award the IDFK without the sin bin IN THE CONTEXT OF THAT MATCH, then so be it. Context is important, the player who ran up to dissent about a decision 30 seconds ago where a throw in had been taken since received a sin bin - that's not acceptable to me. Someone getting emotional because he didn't agree I'm somewhat sympathetic to - you have no idea what is going on in these people's lives. The example above apologised to me after the game, while the coach said it was the first sin bin they'd seen in three months. This leads to my next Jackanory.
A few weeks ago I did a game on the line with a former L3 in the middle. Before the game the three of us were discussing the introduction of sin bins from S5 down as he wanted our opinions. I said I was a big fan, he was completely against - context.
About 25 in a striker was unhappy about elbows - was in front of me, probably too close buy seemed ok, ref in line 15 yards away, didn't seem a problem either. Ball went up the line and out of play, he whinged at the ref who told him to get on with it. Striker told ref to f off. Ref stops and has a chat. For me that's a sin bin, I'm not having you follow up an explanation with an expletive, but he didn't. At half time he said he didn't because only he and I heard it.
On about 85 he gives a "soft" free kick against this strikers team, 30 yards out from their goal, when they are 1-0 up. Striker runs 40 yards to complain. He gets a yellow card on the "totting up" not for dissent. Again, not the decision I would have given. 20 seconds later he gives a second yellow for something in the wall, so this player is sent off.
Now, I'm not a former L3 and maybe I interpret the rules to my own ends on occasions, but that is not how I would have handled that. A dissent yellow on 25 might have set a tone, one on 85 would have stopped a red being issued and everything that follows on from that.
I consider my "job" is to manage the game to let people play and enjoy football, the rules are a tool box not a hammer - select the right tool for the task at hand. I'm told higher up the pyramid assessors consider the job is to apply law 100% accurately - I will stop at the level where someone tells me that what I did was right in the context of the game but technically wrong (or they feel I interpreted it incorrectly) in law and marks me down. I want to enjoy refereeing and the players to enjoy football, this isn't a career for me it's leisure.