For those of you who are going deskless, here are a few photos of my classroom to share what I do to prevent those chairs from migrating around the room. Especially if you have a big room you will see that it is hard to keep the chairs tidy without a little organization.
At the beginning of the year I organize my chairs in a large horseshoe (with a small section in the middle because I need to fit 40 chairs into a room made for 28). You can click on this photo to get a closer look:
Each group of 6 chairs is inside a colored rectangle. Students place their bags against the wall and notebooks beneath their chair. They are allowed to have their feet outside of the rectangle, but all chairs remain inside the rectangle:
I use two different tapes; I start with colored masking tape and really ground it into the carpet with my shoes. Then I covered that with clear packaging tape, which has superior resistance to all of the scuffing that kids will do. For seven groups I used two rolls of clear packaging tape ($2 each at Staples for each 800 inch roll of tape) and 7 rolls of colored masking tape ($3 each, but I have left over to use on future projects).
After two weeks it still looks beautiful and everything is nice and tidy. Here is a close-up of the worst damage, where a student has pressed down while pushing his chair back repeatedly. Most of the time chairs glide right over the clear tape, so he must have tried extra hard to leave his mark:
Ultimately going deskless has given me more control over my classroom, but if I let my desks wander around the room it would have driven me crazy!