[M. Bison]

I'm assuming by reason you're asking for: any area, on any current mg map, where !block can have a legitimate rule-abiding purpose or use on the server.

I do not regularly play on the MG server. In fact, I probably haven't even played the majority of maps on the server. I can, however, point out a potential 'reason' with relative ease. I will point out that relatively all objects in mg_lego_builder_v1 are setup in a manner perfect for boosting. Almost every single instance of boosting onto these objects would be acceptable. These very same objects can even be gotten onto without block by jumping off the yellow towers.

Furthermore, here's a few things to think about:

1. The default behavior of CS:S is to disallow player collisions (blocking is default).
   
2. A CS:S server cannot allow player collisions (noblock) without an unofficial nonstandard 3rd party plugin.
   
3. The author of mg_lego_builder_v1 made no mention of noblock. Therefore, the default behavior of blocking is assumed correct, unless contradicted in some way, such as:
   • The default spawns are stacked on top of each other. (they aren't)
     
   • The default spawns are so tightly packed, players are closed in and cannot move without others getting out of their way. (they aren't)
     
   • There's a way for players to get stuck inside each other. (there isn't)
     
   • The server rules prohibit it. (we don't prohibit blocking on this map, with exception to the patched spawn exploit.)
     -- Take the example of a standard map like de_nuke. That map has some unacceptable boosting areas "exploits" which will get you banned from most servers and leagues.
     
   • The default behavior of blocking contradicts with or is not suited for the current objective. (blocking on this map is mostly* acceptable)
     *The spawn does have an issue which potentially conflicts with what's accepted and acceptable, but it could very well be a bug or even a feature envisioned by the author.
     

To reiterate, blocking isn't always acceptable (even when it was desired by the maps author). The server rules overrule everything, regardless of whether it's possible or intended by the maps author. There are occasional valid and invalid uses for block. Players should use common sense and their discretion before attempting to boost onto something. If you have any reason to believe something isn't fair or permitted then clarify with an admin before doing it. If you don't, you're risking admin retaliation. Don't be surprised and complain when it does happen. Your complaining will be shrugged off.