I agree with POLOGREEN on the letter of the law but I also disagree. So, if that scenario is right and they did not offer then if a coach has a hit and run on and the ball is 3 feet above batters head and they swing through at waist high to protect the runner did they offer at the pitch? The bat staying out there could be considered an offer at the pitch according to the umpire's interpretation no different than a swing at a ball 5 feet above the bat would be considered swinging at the ball by everyone but it is really not an offer at a pitch. I would say 90% of the time if you leave the bat out there the umpire is going to call it a strike because most will say you were just a bad bunter.
The danger part of slashing is not the offensive team it is the defensive team. You have to teach your defense to read the batter and bail if they have to. I faced a guy who used to coach HS softball so he would teach his first and third to come within 20 feet of home plate when the batter squared. He would yell hold your ground. I watched a player from another team slash and almost took the third baseman's head off with a shot. The coach said great job of holding your ground. His mom yelled get your +++ out of the way next time and told then lit into the coach.