Fredericksburg lot at VRE filled

Ok, why is it that seemingly random days the Fredericksburg lot at the train station is full? I was able to snag one of the three remaining spots this morning before my train. Normally there are a dozen or more spots when I arrive. Why would it be packed on a Thursday? Was there congestion early on 95? I understand when the weather is bad, or at the biginning/end of the fiscal year when gov workers usually can't get travel approved. This happens several times a month now, so maybe more people are taking the train!
At first thought, this would seem random, but that doesn't seem to make sense. Most people that ride the train have a pattern - same parking area, same car, same seat - so there must be something changing the patterns several days out of the month.
At worst, it just means driving around the corner to the garage for a few $. Take my advice, don't park on the street. That sign that says permit parking only doesn't mean your f'burg city sticker - or you'll be making a donation to our police department.
Glad to see more people riding the train. Most people that know me know that I advocate for mass transit that makes sense - and I'm a huge believer in commuter rail along I-95.