Funny that there is an old Chinese idiom 凿壁偷光 (záo bì tōu guāng) referring to this exact act. The idiom literally means "to pierce the wall to steal a light" and the original story goes exactly like how a man wanted to read books but was too poor to afford lights, and he just pierced the wall to steal lights from his neighbor.

So yeah, to Chinese, it is stealing. But the funny thing is that Chinese also think the man in the story is keen on studying, and this idiom is actually used as a praise to people who never stop studying even during the hardships.