No one stopping anyone travelling. You can go anywhere in the EU for 90 days in any 180 days. If I want to go to the USA to see my lad, I fill in a Visa Waiver form, pay a few quid and it's approved virtually instantly, lasting me for 2 years. It's not really a hardship. When we played in Moscow, plenty on here got visas.
The issue I have with free movement is economic, not because I don't like foreigners. It's pretty well the same argument Nobel prize-winning economist Joseph Stiglitz uses in his book on the Euro, though he puts it much more academically rigorously than I do. It's the same principal as in chemical osmosis, when you have two solutions of different density and a porous boundary. The higher density solution migrates to the lower density one until equlibirium is achieved.
People from poorer countries naturally gravitate to richer ones, as we've seen with the influx of Eastern European people from Poland and Romania. Yes, many of them contribute to our economy but they also consume resources, such as accomodation and medical services, which are finite and difficult to scale quickly. The more skilled they are (doctors, engineers, etc) the more they earn in the richer country, which is skills they deprie their home country of, as well as the tax revenue they could have contributed at home.
So the poor countries get propped up financially by those richer ones, as we've seen with the net flow of EU funds from countries like us and Germany to the likes of Poland & Romania. So it's just swings and roundabouts really. If the EU was a level-playing field, with wage levels, tax levels, opportunities & infrastructure all similar across the community, then free movement would be no issue economically. But like those chemical solutions, it isn't. There is no equilibrium. What's the incentive for countries to develop and increase their skills base if those skilled younger people just fuck off somewhere else when it suits them?
So of course people in the UK see free movement of people as a good thing because we essentially attract lots of cheap labour. But that cheap labour here isn't a good thing for the countries the workers have come from. It's one of those great liberal ideas which is the effective replacement for colonialism, except we're taking the skills from these countries rather than the raw materials.