Firefly, Lightning Bug, or Milkweed Bug?

A few years ago I spent a lot of time with a very friendly firefly on our tiny patio garden. I even got him to sit on my arm and it made his girlfriend quite upset. I had never seen one so up close, and found it fascinating. This morning on our walk to the national mall, we always stop by the gardens around the Smithsonian castle. I was admiring the succulent plants in a pot right outside of the entryway to the visitor center. Then I noticed three little black and orange bugs with black legs sitting on one of the plants. They weren't afraid at all having their photos taken. As we made our way around the gardens, we ran in to one of the employees who asked if we had any questions - as we were admiring the purple leaves with pink flowers plant. I showed him the photo of the bugs and asked what they were. He said they were lightning bugs. I told him I had seen fireflies up close, and if lighting bugs were the same thing as fireflies, that wasn't the same bug. He assured us they were. So when we came home I looked up orange and black insects and milkweed bug matched the description. I had never heard of them. What amazes me is not the milkweed bug, but the fact that someone speaks so confidently about something they don't know what they are talking about. Seems to be a problem in this town, even when it comes to bugs.