The command is there for a reason. If i had to guess its used to make sure the client is "synced".
Imagine player A multitasking out of CS, and playing around for 2min. Then comming back into CS. His client is now be slacking behind 2min, and when you block the fullupdate issues will happen.
I also think its called when starting to record a demo. So even more issues.
The fact of the mather is that a plugin that uses ResetHUD is not properbly made, and there are other ways to make the event trigger. You should post a bug report about the plugin instead of trying to fix the expoit(Yes i use ResetHUD in 1 of my plugins to

But its still bad programing practice )