Weird question...
My Watsonian guess: boots fill with water quickly, and can drag a man down. I think it's common practice among sailors to lose them if possible when gone overboard.
My Doylist guess: well, Ariel's feet were (in)famously well-drawn in the scene where she explores her new legs. Somebody on the team probably has a foot fetish.
Fresh-eyed movie blogYeah, I'm gonna go with a minor foot fetish on the part of someone in the Story Department. There's quite a lot of Foot Focus in that movie for it being a Disney cartoon.
I think it was one of the I Love the 80's that called TLM Disney's foray into "softcore porn." Ariel surfacing as a human, taking a heaving breath and arching her back in order to fling her hair, all while backlit and wearing nothing but a seashell bra...that's pretty racy for a G rated picture.

Something I've always wondered is why Eric's boots are off when Ariel has brought him ashore. Is there some reason the animators had him barefoot?
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