As time has passed, various measures have been implemented to prevent takeovers in different kinds of IRC server software.
The simplest way to prevent this from happening, implemented in IRCu, is to check which channel is newer when two merging servers each have a channel with the same name. If they were both created at the same time, they were the same channel, and operators on both sides should be kept. If one channel is newer than the other, this channel was created later, possibly as a takeover attempt. In this case, the special status of any users in the newer channel is removed when merging.
Many servers have implemented Services, automated bots with special status, to protect channel operators. They usually implement some sort of login system so that only people on a channel userlist can gain operator status on that channel. This also convenient for the operators because they do not need to have an operator on the channel all of the time to keep their status.
Channel creation during netsplits is not the only kind of takeover attempt, however. Other methods include cracking the computers of channel operators or stealing their Services password.