They are concerned that Brexit may ultimately lead to the break up of the EU (it won't). They are concerned that we are net contributors to EU funds so losing our money would hurt (I couldn't possibly comment on that because the issue is complicated). Well, that's the German politicians views, I suspect. I'm sure Suff will have better insight.
Yer average German citizen probably couldn't care less whether we stay or go. Possibly prefer us to go given we're the bolshy off-islanders.
I am less concerned about Merkel's meddling in our referendum than Obama's heralded statements. By what God given right should he or Kerry have any say in our affairs? How would the general population in the USA react if Cameron made a series of public interventions about curbing gun holding?
On a related EU-propaganda tack, there's a very run down part of north-west Birmingham that fringes either side of the Soho Road between the City Hospital and Cape Hill. There are signs up that they are "improving" the main drag, which means resurfacing it and putting in speed humps etc amongst other measures. There's a sign up on a lamp-post at the start of it all that the improvements are being funded by the EU Regeneration Programme or somesuch ....
I know it would be illegal under both British and EU law, but there are times you could wish that you had a can of spray-paint to hand ....