I would have assumed the office would be closed on the 4th. When I had regular weekly appointments, if a holiday was coming up on my appointment day my t would typically remind me the week before that we wouldn't be meeting the following week bc of so and so holiday. So, while I would assume the office to be closed on the 4th, it's also not unreasonable to think the t should have mentioned it.

I'd bring it up, not in a confrontational way, but in a "hey, this kind of thing bothers me so I wanted to let you know", kind of way. Unless it's a last minute trip, the t knows what's coming up and should be able to give you plenty of notice regarding changes. Perhaps if you let her know how last minute changes to the schedule are disruptive for you, she will be more on top of it.