I assume you are monitoring the current situation about COVID-19?
I figured I would chime in here, as I've been working on COVID-19 in the Canadian equivalent of the CDC since the very first reports of a novel coronavirus out of Wuhan. This includes working with and supporting a team of epidemiologists with travel expertise, the nurses responsible for quarantines at border crossings and on conveyances, messaging and signage for risk reduction at airports for travellers, and the team that posts up to date outbreak information and risk levels for travellers by country.
To be clear, I'm talking just as a member of the public, and my views here are my own and not reflective of any government or agency or policy. I am not a major decision maker. But I've also worked on this outbreak non-stop, including weekends, nights, etc. from the first reports of the coronavirus to present.
All that can be done at this point is to monitor the situation to determine if there is sustained community transmission in Denver come June. I know the organizers of keycon personally, and have attended several events in the past, and speak with them regularly. They are intelligent and up-to-date on current events, and I have every confidence that should a situation arise where the event needs to be postponed, they will do so. Thankfully, the demographics that are most at risk (the elderly, people with compromised immune systems, and those with chronic conditions) are unlikely to be in attendance.
There are steps that can be taken prior to and during the event that can reduce risk. All attendees should:
Wash your hands regularly with soap and warm water for at least 20 seconds. This is the most simple and important advice anyone can give.
Use alcohol based hand sanitizer
Have antibacterial wipes on hand that can be used to wipe down boards/caps, especially if people are trying them out
Cover your mouth and nose with the crook of your arm while sneezing/coughing
Buy trip cancellation insurance, and ensure that it covers things like cancellations due to infectious disease outbreak (some insurance companies are no longer providing refunds for COVID-19)
Avoid prolonged personal contact, such as shaking hands
Avoid touching your face, nose or eyes
Avoid contact with sick people. If you start to feel sick, isolate yourself as quickly as possible. If you start to feel ill before the event, PLEASE reconsider attending, especially if you are coming from an area with a confirmed outbreak.
Check your travel plans regularly to see if there has been any change in status. This can change very quickly and without much warning.
The truth is that no one has a crystal ball, and the situation is changing so quickly on a day-by-day basis that trying to predict if there is going to be an outbreak that affects keycon is not possible. All that can be done at this point is to practice safe hygiene behaviours, stay informed of current situation, consider the advice of your local health authority, and to make the most comfortable decision possible for you as an individual.
Fear is a normal reaction to this type of outbreak. However, I would ask people not use social media as a source of news for anything COVID-19 related. Perspective is important here. Car accidents kill 37,000 people in the US every year. In comparison, there have been a bit over 3,000 confirmed deaths from coronavirus in all of China, the epicenter of the outbreak. I'm not saying the situation isn't serious, because it is. But when I feel my own anxiety rising, that is something I use to bring myself back down.
EDIT: 6 million car accidents, 37,000 deaths. Sorry, I'm tired!