During several exams in the Solent area this year I noticed that the candidate was not allowing for variation in their calculations. When challenged over it the response has normally been some think like, "a difference of 2 degrees is not going to make any difference over the short distances involved".
Whilst I can understand why you might think that applying a variation that is less than 2 degrees is not important, this can be a serious issue which it is important that instructors working in the area need to take on board.
We need to be training students to sail anywhere in the World, not just the place they are taking the course. The next time that student gets on a boat could be on the other side of the World where the conditions will be very different. If they charter a boat in the Caribbean the variation could be 15 degrees, which if the student has not been trained to allow for variation, will sooner or later cause a problem!
Secondly, although when a course to steer to allow for the tide and leeway is calculated it is common to round the resulting course up or down to a figure that is sensible to give the helm to follow, this does not mean that other navigation drills should not be worked to the most accurate figures possible. If there is a variation, it needs to be part of the calculation and students must know where to look it up and do so! I have frequently had students who have just completed a theory course in the classroom use the figure for variation from the training charts used in the theory course rather than checking the real figure on the charts on the boat.
With variation decreasing towards zero on the south coast of the UK, it is going to become more important that instructors ensure variation calculations are covered, it is too easy to take the simple route and say to ignore a small figure, anyone who does that as an instructor is not really preparing their students to sail in other areas and that is an important part of the training, not just to prepare them for one sailing area.