Through Piapro, fanamde characters that Japanese fans created have become acceptable to a degree.  However, Utau (aka Utauloids) are not bound by the same status. While giving a fan made a name, particularly a Japanese name, fans often forget to check the name is not already in use, or that their own desires for the creation do not clash with possible plagiarism of another user's mascot. Particular of note, an Utau owner has the right to demand such a copyright violation to be removed, possibly though force if need be. When designing either a fan made or a Utau, a user must make sure their works do not already clash with another, least they become a victim of the owner's legal fury.
However, one thing to note about official Vocaloids is some mascot designers become particular touchy about their mascot's settings even though unlike Utau they are not covered by the same rules of copyright. Generally a level of respect is given in the Japanese fan base to avoid use the settings another Vocaloid user has used, although arguments have been known to occur over who used the settings first in the past. [Citation needed - December 2010] The most common problem was owed to Pitchloids, that is a kind of fanmade vocaloids who were merely a pitch of a vocaloid such as Akaito. In the past there were so many, in particularly in the early Vocaloid 2 era days, that it became hard to separate them and some even accused the creators of being "lazy". [Citation needed - December 2010]
Regardless of the scenario, many Vocaloid fans even in the western fandom considered it more respectable to obey the various workings of the fan made character process. Also it should be noted that not all the fans accept fanmades.