I get a kick out of this actually, having previously worked with the LCBO. At the time I was a student making in the area of $16/hr (late 80's) stocking shelves and occasionally working on cash. NOT a stressful job. As a casual employee, I paid minimal union dues and had the full protection of the union.
I am not a fan of unions, as I believe they've outlived their usefulness.
So, the LCBO wants to make the majority of their retail staff part-time based? Like almost every other retail line of business? I don't see a problem with it.
In my mind, the only area of dispute is how they make the switch. Turfing existing full-time employees isn't the answer. Offer up early retirement or buy outs might work. Grandfathering in the part-time staff may work even better (e.g. no new full-time employees are hired, all part-time). Over time, the LCBO will get what they want, and current full-time employees will have minimal impact.