Wikitruth has it right: "sockpuppet" is a wonderfully vague and elusive insult that can be used against anyone who disagrees with you on Wikipedia. Instead of dozens of people disagreeing with you, there is only one real person and several sockpuppets!
But when reality begs to differ, Wikipedia's most vicious warriors have ways of making the logs tell a different tale. The warrior finds out the IP address of the person he wants to pin the socks on. Then he goes about the business of creating and grooming the socks. The warriors with more money might even invest in houses in the same city where their target lives, equipping them only with electricity, a computer, and an Internet connection which accepts Web browser commands from the warrior's house. Though that's somewhat of a waste of money, because IP addresses can always be falsified later. Once the warrior is ready to pin the socks on his enemies, he has one of them do something that will grab someone's attention and prompt them to file a Checkuser request. The IP addresses of all the socks are falsified, and the warrior makes sure that none of his enemy's edits overlap time-wise with the socks. But if they do, all he has to do is falsify the edit times for those inconvenient edits. The person who does the Checkuser may either be an unwitting idiot or a knowing accomplice. Either way, the will of the warrior is done.