Visas provided at the airport?
I hear from various (probably totally unreliable) sources that if you're from the UK, US etc. you can turn up in Minsk and they will give you a visa at the airport when you arrive.
How true is this?
Its really up to the airline when you check in to get your boarding pass.
I've never seen the airlines NOT check to make sure you have a visa, before they even let you board their flight. They know whose country's passports require a visa for entrance.
Lufthansa checks your visa first, in the USA, before you board even to Frankfurt, if your final destination is Russia or Belarus. They check again in Frankfurt before they give you a boarding pass on your Russian or Minsk flight.
What's the point of bringing you to a country they know you won't be permitted entrance, when they know they're just gonna have to haul you back out. Rather than taking you to jail, the Immigration authorities hold you in the airport and force the airline that brought you there, to put you on their next flight back at the airline's expense.
The airline pays the price for being stupid enough not to check your documents in the first place. That's why they check first. Maybe its different if you have a diplomatic passport, but if its simply a personal passport, they don't have to let you board without required visa, and they shouldn't anyway.