You didn't tell us yet about how you disclosed to Mrs. S. exactly where you were going. And, in the end, did the trip make up for the comment?
She figured out that we are flying somewhere and since all I had was a backpack she knew it is a day trip. She did not know the destination until we got to the gate
P.S. I especially like your closing photo. iPhone ?
Samsung Galaxy S5. The view was great, the picture didn't turn out so well, the S5 camera can't focus in low light conditions
I love flying in and out of DCA, especially at night. Great views.
Indeed, very pretty
Very entertaining.... Once Avios devalue, your gonna have just tell her you like the coat 

I didn't read it that way. I understood the DC trip as a way to make up for the foot-in-mouth comment about the coat.
This is the correct interpretation, but we both had a great time. The weather was beautiful, the museums and the monuments were great. I couldn't have done this as a day trip by driving. The tickets were listed as $890 each when I selected the late evening return leg.
And, in the end, did the trip make up for the comment?

All Quiet on the Western Front
But seriously, I thought you were taking her to a mall. 
Taking a day off to spend it at the mall? Self affliction has its limits
Thanks for the compliments!
Costs:
4 x 4500 Avios = 18000 Avios

BA fees $22.40
two WMATA SmarTrip cards - $20
Museums - Free
Guided Museum tour - Free
Two audio guides - Free
Dinner Char Bar - $83.49
Parking at LGA - $39
