It's entirely plausible that whoever wrote the script intentionally designed it to submit a large chunk of votes from "Vatican City" to try and discredit the petition, especially given /pol/'s political leanings.
They do. They just removed 77,000 signatures for fraud: http://www.independent.co.uk/news/uk/home-news/eu-referendum... (Which probably wasn't even hard - if you look at the claimed 4chan script, it uses the same postcode for every vote, which happens to be the postcode of the Houses Of Parliament.) The total number of signatures is over 3 million. Additionally, this article is from a right-wing tabloid site of questionable honesty, and is based on taking 4chan comments and random tweets at face value and then accusing the "Remainstream press" of failing to perform "basic journalistic research" for not doing so.
https://twitter.com/hocpetitions/status/747063424132255745