Yet there had to be arena workers to turn on the lights, right? Clean the ice, off ice officials, etc. Is there any concern for them?
If you click the link you will see the team employees filled those roles. Ticket sales people were cleaning the ice, COO was running the AV, etc - a real skeleton crew, and people who were probably already at the rink when the decision was made. I don't know the exact conditions, but assuming it was expected to get worse as the night went on, as an employer it isn't always about getting your employees to work, it is getting them home safely afterward. The less people you bring in, the less you need to worry about travelling on dark, wet, icy roads. In fact, its possible the team put those few salaried employees up at a hotel along with the team if it was bad enough.
Most arenas have at least a security guard and/or maintenance person on site at all times, but just enough to maintain an empty building. Once you let people in, you need enough to keep an eye out that no one goes "exploring" where they don't belong, etc.
Once you open it up and say "come if you want to, but we don't advise it", you don't know if you will get 10, 100, or 1000 people. I wouldn't be surprised if two fans who drove down from Bridgeport and stayed at the hotel next door showed up at the employee entrance and explained the situation the team would have made and exception let them in - they just wouldn't publicize it.