Random wrote: Is it the comics shops fault, or is it possible that IDW is not doing enough copies?
IDW print on the basis of orders they get through Diamond, plus a bit extra. That means they're not left sitting on stock they have to pay to store.
Either the store isn't ordering (quite possible; most stores order less of each title as a series goes on, because they expect sales to drop off and also don't want to be left sitting on stock) or they are ordering and there's more interest now with the movie. Quite possibly a bit of both; I know some stores have upped orders of everything TF because they're anticipating/found cross-sell with the movie issues.
For any comic that isn't in the top 10-20 of the Diamond sales chart, it's worthwhile reserving. Gives stores a better indication of what's going to sell.