Originally Posted by mrmaico
From the 2005 GS owners manual: A spare key attached to the same ring as the ignition key used to start the engine could 'irritate' the electronics, in which case the enabling signal for the ignition, fuel supply and starter is not issued. Under these circumstances the motorcycle will refuse to start. Consequently always keep the spare key or keys separate from the ignition key.
The highlighted portion is the "key" It is only a problem if the antennae sees more then one coded chip when it polls upon the ignition switch being turned.