Is this a genuine defense strategy for AR or is it just Christmas time?

Some people (including me) just simply don't give a fuck about AR anymore.

I've seen some people do that too. I haven't tried it myself though, but theoretically, since it's only one unit, it could possibly mean only -20 Lift per day.

Though what I saw was even more mean. They put the Aether Items behind the character so you cant reach them at all, since the 1 enemy unit blocks the way to them and when u attack them, the raid is over, so it's literally impossible to get the Aether Refills. It's a scummy strategy though, so I advise against it.

Nah. I do the same basically.
Just put 4 level 1 units on my map since I don't care about losing lift or not. I don't plan to be competitive in that mode, just playing it to get some grails.

Somebody did that to me but placed his single wrys in a position that only allowed me 1 aethor pot destruction, when I needed to kill both pots for an extra raid. I was fking pissed :<

I did this before rank 11, since ranks are shared and theres really no benefit in depriving others of lift when you stand to lose none. Still do sometimes at the end of the week once Im "safe".

Not this week, mind you. I finished 20 aether from rank 18 and I want to watch the world burn right now. My defense is actually pretty mean this week. From the picture linked: Veronica has restore, olivia has guidance, ophelia has a quickening seal. The tactics room is rank 2 and meant to be "bait". T1 enemy phase veronica moves to remove panic from ophelia, oliva moves to dance veronica. If the tactics room was destroyed ophelia will move to where it was via guidance and drop an aoe special. Going from the left is probably the better choice, but even so veronica wont get baited unless you give her a 100% kill (afaik). Ive seen exactly one team make it through this without losing a unit (out of like 8 or so since I set it up like this). That was a flyer team. Personally none of my teams can, and I have the benefit of knowing exactly how it works lol.

I guess you can call it scummy or cheap, but I spent a lot of time making it and Im kind of proud of how eff'd up and rage inducing it is.

Still pissed off about just barely missing rank 18 >.< Gonna lose about 700 lift at reset... gfdi. But hey that was coming from 16 so I think I did pretty well. Right now Im around 3400th place, but Im sure Ill get knocked down to a bronze chair before reset. lol.