Not true, you can issue assets on any server that has not disabled the ability to issue assets.
By default OT allows anyone to issue assets (though obviously only the nym that actually signed the specific asset's contract can asset that specific asset that they signed).
The OTdemo server demonstrates this ability of anyone to make up and issue any asset they choose.
-MarkM-
You are obviously correct too but then the issuer is at the mercy of the server owner. I know how that can work out
pi..pi...pio.. (spits)