[Maru]

No, the system doesn't expect the voter to be completely infallible... it is dependent on their influence, but it's not like a voter can be absolutely have it all established for them before they hit the polls. It's not always a fully informed vote... it's impossible for the voter to be 100% aware of all the facts anyway at all times... not everyone can decipher information to that level or understand what it means... they only care what it means for them*. Sometimes, a vote from the gut is more than ample to get a fair result... they voted with the information they had at the time. Doing another vote will not necessarily "invalidate" the last result... if the new result were too close, then it would be very contentuous... plus if there is another referendum, it's possible that may "pollute" the waters so to speak, because then people will feel well... maybe I didn't have it right the first time, since they redid the vote. May actually suppress their vote or confuse them further, so it would not be a true result anyway...

* Now, I think the exception is when the circumstances behind the vote change entirely. Say Brexit will actually happen fundamentally different than how it was described on the ballot... then a new vote should be done, as it's technically a new referendum. Say Brexit was about leaving the union, but then became a totally new type of agreement... then it's important to get a new result I think if the actual outcome would be completely different than what was polled... unless for reason, Brexit is completely unreversible (can't go back to the EU, etc)... then I think that should probably be handled at a high court level, maybe referring to the constitution in those instances, what the default would be, etc... because then I think it would be far too technical for the voter to effectively decide...