For better or for worse, that's my general Classroom Management strategy.
When I was seventeen and a 'wet behind the ears' civil servant, the Deputy Area Manager said something to us new recruits that appeared quite flippant. However, it was a statement of his style and it has stuck with me ever since.
He said, "Dance on the tables for all I care. Just get the work done!"Admittedly, I didn't dance on the tables but I did get the work done (mostly). So, fast forward to teaching.
I encourage collaborative and cooperative work in my learning environment. Equally, I understand that I am limited to the current furniture and fittings and this arrangement doesn't always fit my collaborative philosophies.
So I allow my students to 'break out'. My openers tend to conclude with, "Sit where you want. Sit on the floor; sit under the tables for all I care. Just make it about the work."
(By the way, students are not allowed to sit on the tables)
Some students take me up on the offer. I have a few 'regulars' who like to sit on the floor, leaning against one the walls. Very occasionally, I get a couple who actually sit under the tables. They start off believing it is a bit of fun, but they soon adopt this space as a working/learning space.
All I am trying to achieve is to make the learning environment more about the student than about me. 'Sitting in rows' suits me as someone who needs to maintain order and control, but it doesn't necessarily suit the student who is trying to achieve the best learning possible.
I haven't had anyone walk into my lessons recently, but a few years ago, my old headteacher did walk in to see 3 students sat under a bench. Although an eyebrow was raised, he did understand and appreciate what I was (am) trying to achieve: to create a personalised learning environment in a not-so-flexible environment.