But yeah this has been handled poorly by Blizzard, with pre-pay users having problems and my wife not being able to play as they don't let you change country without sending in a photo of your ID.
I'm curious because in playing some other games that have detailed 3rd party stat trackers, a lot of users I thought were for sure smurfs actually weren't.
Like someone in the match would have a 50% headshot rate, but their career or season average was like 7%. It looked like they were just having a really lucky game. With 10 or 12 players, it doesn't seem crazy that a good portion of games have 1 player who's just playing a better game than they normally do.
Smurfs in overwatch (1) were incredibly obvious because
a) each players 'level' - which correlates directly with hours played - was prominently displayed, so new accounts were immediately identifiable; and
b) as a hero-based shooter, there are various macro strategies and hero-specific techniques that genuinely new players simply can't be aware of
Many smurfs would also have unintended "fancy" battle.net tags - think ツ kinda thing - which were only available by initially purchasing account with region set to an Asian country before then changing it to US.
At it's worst, one would simply look at the player names and levels on the loading screen and know which team was going to win before the match had even started.
Combined with relatively long match times and the inability to forfeit in Overwatch; the end result is many, many hours of dead rubber games over the years.