No, there is no election in Reykjavík on the day of this event. The next Icelandic municipal elections will not take place until 2022. The title concerns the 2018 Polish local elections and in particular the second round of the Warsaw mayoral election, which will very likely take place on the day of the event. As the date of the second round was announced months after I booked my tickets to visit your beautiful island, I will be very disappointed not to take part in it.
So I thought maybe some local and international geocachers will be able to comfort me by attending this event. We will meet at the coordinates at 7.30pm local time and stay there until 8pm, which is the precise moment, at which the voting will end. We will exchange trackables, share our geocaching experiences in Iceland and, hopefully, have lots of fun. And if we are lucky, we might get to see the northern lights. But I have been told not to get my hopes up too much about that last possibility.
It is my understanding that the parking coordinates provided in the listing are free for everyone to use and that the bus stop mentioned as a waypoint should also work just fine as an alternative way of getting to the event. If any locals disagree with any of those two pieces of information, please let me know, and I will update the listing accordingly. It is also my understanding that it may get quite chilly, so please wear some warm clothes, as the entire event will take place outside.