That's a pretty decent reason to be honest.
Only if that single issue is the only one he cares about, or it's so important as to outweigh every other issue.
I currently do business in France, Italy, Spain and several non-EU countries. I don't expect my business in the three EU countries to change much, whether the UK leaves or not. If it does look like changing, nothing much is going to happen for at least a year or two, and that gives me plenty of time to adapt.
And while my voting decision isn't made for definite, nothing I've heard yet changes my inclination to vote to leave, and for reasons several of which are nothing to do with trade or business.
If leaving means I have to get business visas, so be it. It'll be a minor irritant, but no more so than doing business in the rest of the world. If the EU decided to be obstructionist and put up so many non-tariff barriers as to make operating in the EU unattractive, it still leaves the rest of the world and at least for me, that's where the growth is anyway.
Given the economic state of several EU nations, and I don't just mean the obvious basket case, but also the ones I do operate in (France, Italy and Spain) the viability of continuing to operate there is very much in doubt for me anyway. If the EU makes it even more awkward out of petulance or spite over leaving .... okay, bye.
What it doesn't amount to is good reason for me to not vote leave.