There are a few ways to go about this:

1) # chmod -x /usr/bin/quota
   This prevents quota from running.  It's also a self documenting flag
   in that a future system manager who tries to run /etc/quota will get
   the "can not execute" error message.

2) # chmod -x /usr/bin/quote /etc/edquota
   This appears to turn quota's completely off (which is what I
   suspect the vast majority of people want) and not only speeds
   up the login process, but you don't get any annoying messages.

3) # mv /usr/bin/quota /usr/bin/quota_check ; cp /bin/true /usr/bin/quota
   This will still make the login program do the quota-check, but at least
   it goes by very very quickly now (as opposed to actualy checking every
   single NFS mount with quota, and so on).  Then, just run quota_check
   whenever you want.

4) Remove the DiskQuota product ("swremove DiskQuota").  This will still
   allow you to keep using quotas, as long as the NFS server still has
   quota enabled, and is exporting the home directory filesystems with all
   the quotas enabled.  Watch out though, since this deletes
   /usr/bin/quota.  So make a copy before removing the package, if you
   still want to have the ability to do "quota -v", etc..