This fixes crouch spamming, could be useful for some people. Well, when I was doing my xdream surf server on cs:go (wich I rarely play), I noticed that there was some duck restriction.. So after doing cl_pdump for dumping netvars and see what happened, I saw m_flDuckSpeed being close to 0.
Don't forget that sv_timebetweenducks needs to be set at 0!