I'm pretty sure there are not "different rules for different people," but when you're trying to accommodate a really large group you do present unique challenges to a restaurant. Large groups typically stay at a table longer than normal sized groups, and this puts different scheduling challenges on the folks that assign PSs. Also, the requirement to have this many diners seated together means that the dining room must block out specific tables for your group, and therefore those tables are not usable for a period of time before your group even arrives... A group of 26 does displace a lot of other diners. Especially if you are traveling during a peak time, you're going to need to be flexible!
With a group that size, I assume you're working with a Grand Gatherings or some sort of large group coordinator?