Graz bans mobile phone noise from public transport

I just read that mobile phones will only be allowed on busses and trams in Graz if they are in silent mode—so no ringtones, no SMS notification noise, no game noises etc. Also no phone conversations. (You don't have to switch it off completely, it just has to be silent.)

At the end of the article, it said that the local public transport company "fears that many customers may, in the future, decide to abstain from using busses and trains because they essentially cannot telephone any more".

Is this really something so dastardly, not to use your mobile phone while you're on your train? People put up with not being able to do other things (such as smoke) while using public transport—is this in a different league?