That presents a real problem in dealing with identity theft legislation, but it is one that we were very aware of as we were developing the legislation.
The offence of personation, which this bill will rename as identity fraud, only applies to a person who pretends to be a real person, living or dead. The offence of personation does not apply in the case of a person who uses a purely fictitious name. As well, the offences of identity theft and trafficking in identity information, which could apply to the handling, possession, and manipulation of fictitious identity information, are only complete if there is an intention to use that information to commit another crime.
So in fact I think we can be quite confident that there isn't anything in the Criminal Code, currently or in this bill, that would criminalize people who use a pseudonym as long as they're not committing other crimes at the same time. But in terms of merely using a pseudonym, for instance, as long as it's not a name that refers to a real person, I can't think of what offence that might be.