For labeling zones on sheets, users are limited to three label functions using alphanumeric characters in Location Sets. Zones are labeled A, B, C, D, etc. We have the typical 4 zones per sheet. This works fine for sheets 1 through 6. Once you get to sheet 7, after the letter Z, it labels zones with special characters like [ and \. This is not very smart, especially given the way that highways label the cross sheet graphics in a pair of brackets. The cross sheet graphics can then look like [ [ , 2 ] which does not make sense to most people.
It would be better if the label function went to AA, BB, CC, DD, etc., or AA, AB, AC, AD, etc., after the letter Z. It would be even better if we could define our own label functions for Location Sets.