I don't think this is a great argument. The reason is that Rubella/German measels is in the majority of cases very mild, in many - people will not even know they had caught it. If you take a large enough sample you'll absolutely find people winning a lottery that they really don't want to win, but the exact same logic is used to by people to avoid vaccinating. For instance the MMR vaccine can cause all sorts of nasty things in extreme cases, but in the average case it's believed to be mostly harmless. Though of course we're always discovering new things about medicines. There's even new side effects in e.g. tylenol still regularly being discovered and published about.