Didn't see this until now, I guess the best case for now is to try to get done early :>

Hey, cool that you come again

Do you have someone with a key secured?
I'll come with a key and my group a bit before 7pm, though we typically leave at around 10:30pm - according to your event (and last time's experience) you play longer than our sessions, so someone else will have to close up.

RPGVienna would like to come again on the 14th, should it go as well as last time ( we really loved it). We will make an attempt to make this a more regular location and talk money and keys with you guys!

For now someone who could open up for us would be great. Depending on registrations we will need around 3 people