Since I've been complaining about just these aspects of the Liberal Green Shift, I am most happy to hear that
...Dion will announce that part of the $1 billion contingency fund in his plan, designed for tax relief to address the unavoidable costs associated with the carbon tax, will be set aside for truckers, farmers and fishermen.
As to the timing, well, it is unfortunate that the annual Liberal caucus retreat should come on the verge of an election call, and therefore that some media should refer to the changes as "concessions" made in response to negative polling figures. But it was clear from the beginning that the original Green Shift was being put forward as a basis for discussion, and that alterations might be made as a result of concerns expressed during that discussion.
In response to these charges, I like the "we listened" line Dion and Co. are employing. They might also try a variant of the line John Maynard Keynes made famous: "When the facts change, I change my mind. What do you do, sir?"
As an aside, the notion that such concessions "weaken" the plan is surely true but politically unavoidable. Best to get a framework in place and then work at tightening up loopholes. Don't let the perfect be the enemy of the good, and all that.