It doesn't specify what the penalty must be, however (does it?). For example, US Code, in the criminal section (506) it says:
(d) Fraudulent Removal of Copyright Notice. —
Any person who, with fraudulent intent, removes or
alters any notice of copyright appearing on a copy
of a copyrighted work shall be fined not more than $2,500.
They could make singing the wrong song a $20 penalty and presumably still comply with the treaty.
Consider how bad the sex offenders registry is. Now consider that that isn't even a criminal punishment (which is why it can be retroactively applied and extended, which a criminal punishment cannot be).
So it could work out to a nothing fine and all is well, but I would highly doubt it ending up as such.
