There are lots of people on Twitter advising voters to take a pen to the polling booth in case their votes are rubbed out.
A lot of them seem to be UKIP voters.
But there's paranoia north of the border, too, among SNP voters scared of dirty tricks by the "bastirt Tories".
As you might expect, there's been a certain amount of mockery from other Twitter users.
But it's not only voters for the nationalist parties who've got the heebie-jeebies. Lots of people who don't give their allegiance are concerned.
This isn't the first time people have had this worry. During the Scottish independence referendum, some voters had the same concern.
There isn't really anything to worry about, though.
And if you're still wondering why we're given pencils rather than pens, here's an alternative explanation.
Tom Chivers is a science writer for BuzzFeed and is based in London.
Contact Tom Chivers at email@example.com.
Got a confidential tip? Submit it here.