+
+ To prevent this from allowing net-rides on the channel, we
+ clear all ops from the channel.
+
+ (Scenario for a net ride: c1 - s1 - s2 - c2, with c1 the only
+ user in the channel; c1 parts and rejoins, gaining ops.
+ Before s2 sees c1's part, c2 joins the channel and parts
+ immediately. s1 sees c1 part, c1 create, c2 join, c2 part;
+ c2's join resets the timestamp. s2 sees c2 join, c2 part, c1
+ part, c1 create; but since s2 sees the channel as a zannel or
+ non-existent, it does not bounce the create with the newer
+ timestamp.)