Would agree with all the above however...
Many moons ago whilst operating from Japan, where the services are at least as fastidious as other 'cold' environment places as parabellum mentioned, we asked for a de-ice and the crew only de-iced one wing as the other was sitting in the sunlight as the early morning sun rose and it's ice had clearly melted off.
We questioned this and were told that this was 'standard practice' for a well know Japanese operator for whom they worked.
We asked for a symmetrical de-ice which was carried out without any problem to their normal high standard.
Clearly therefore there are differences between operator's standards in such circumstances and thinking about the cost and environmental damage of deicing agents, perhaps there is room for more discussion on this.
Comments?