I put fairy lights in dd's room when she was a newborn, so I could see at night to feed her without turning the lights on. Did she become reliant on them? Absolutely. Do I care? Not one bit.
She still has them at 10 years old and nobody minds. It's a tiny strand of 25 lights, on top pf her armoire. On vacation I just bring a nightlight, she has never minded. Granted, they aren't over her head, and never were, but I don't mind baby getting "hooked" on something if it's not something that will need to be taken away at some point. Kwim? Like, I gave her a lovey in the HOPES that she'd get hooked!
I'd get another set for future backup (or 5...LOL.....) and I might move them across the room but well within her line of sight. But other than that I'd not give it another thought.