Being realistic. It makes perfect sense to shut down the trade with the UK. The motor manufacturing industry for example have already said they will restructure and move manufacturing to within the EU. That's billions of euros being invested in the EU sector providing them with more jobs taxes and profits. Than would be invested if the UK stays in and keeps manufacturing here. It makes perfect sense to encourage Japanese and American wealth into the euro sector by shutting the UK out. The long term benefits for the eurozone by playing hardball are immense. Just look at rover and mg. the buy out was dropped and all British jobs lost and debt dumped. BMW took the rights for the mini and China the rights to mg. that's millions lost to the UK economy from one car manufacturer being allowed to fail and the profit of mini and a revitalised mg now being built abroad. Profit for foreign investors that has left the UK. Now consider how many sectors of industry have said they will leave the UK. Aerospace Cars Commercial airlines Etc. So does it make sense for them to let us drop out and not offer new trade deals. Totally. The reason the stay party campaign is fear led. Is because they know how bad they have messed things up not preparing better for it.
A close vote would encourage other nations to push for one too, the EU cannot continue as it is, that's for sure. If Cameron was a smart man, he would have handled it very differently and probably got what he wanted.