Underage people and foreigners are in the 'unable to vote for perfectly normal reasons' bracket. Extrapolating from census figures, you'd need pretty much every single person in the 13-17 age range to vote Tikhanovskaya to make up the disparity between Telegram and official tallies though. And if she got literally every teenager in the country to register a protest vote on a web app, there's a sneaking suspicion she might actually have got more than her 10% official tally with the adults too...