I think it depends on a few factors. For me myself I have no problem with it, but there are those that have an interesting view.
There are apparently two types (three if you count actors at parks) types of costume makers. The Cosplayer, the Costumer, and the Charplayer.
Cosplayers: As defined by some costume makers, usually is seen as a younger person who tends to act out the character more, thus the term Costume player.
Costumer on the other hand is: defined as someone who creates elaborate costumes and wears them. They don't normally go into character, they're just there to show off their handy work.
Charplayers are: usually hired by parks to play a character and buy their costumes rather then make them when they are at conventions.
I think it all depends on who you talk to. I've talked to Costumers who don't like the idea of being called cosplayers because they see it as too young. I've also seen Cosplayers who don't like being called costumers because they see costumers as not really being part of the cosplay scene. Then there are Character players who seem to just be like, hey I'm cool being called either. Most cosplayer/costumers/charaplayers seem to actually be okay with dressing up in whatever you want. I think the only time to worry is if you're going to a trek convention and you walk in dressed as Han solo.
To be honest Anyone that claims that you can't cosplay as you like at a convention then they really must be a grinch.
This post has been edited by Dark Spellmaster: 27 February 2013 - 02:48 PM