Not really. The Leave campaign .... also kept mentioning Montenegro joining the EU and that causing more immigrants. I doubt many people will have gone off and researched the population of Montenegro and realised the population of that country is smaller than some of our cities or considered that Montenegro is a beautiful country which some British people would probably love to live in.
Oh dear. This is a classic example why Up-Tilt-390 nailed it up thread. Because it is more complicated than that.
You are perfectly correct that Montenegro is a beautiful country, with a small population - it's around mere 650,000.
In fact, it's so beautiful that every second upper-middle class oligarch between Vladivostok and St Petersberg has bought a chunk of it. They get residence permits too, you know. And once Montenegro gets into the EU and then into Schengen - if it does - I can guarantee you that a whole lot more oligarchs and lesser desirables will get residence permits and passports. This is the Balkans. The Balkans has some wonderful people. But I'm afraid for many it's a case of forget the law, if you can make money, make money. And that goes up to government level. There are already EU countries in eastern Europe that have made a killing out of selling passports and residence permits - ostensibly for residency in that country, of course - but it's plain damn obvious they are not expecing the residents to stay there.
I don't know if the Leave campaign imagined 650,000 Montenegrins would up sticks and come west - I agree with you, I doubt that 1% of the leavers had a clue what the population was. For me, it's not a problem if 50,000 wanted to come to the UK to work (I doubt it would be so many) - but it's the fact that the legal systems and the understanding of rule of law of a number of these countries is all too weak AT GOVERNMENT level. That is the problem. And I am a (somewhat reluctant) remainer.