There's a (gay, married) woman at my work who has a crush on me (she's told people this). She's also autistic to some degree, and just doesn't get social cues or hints at all. She's constantly trying to get my attention, being over effusive, if I assist her with anything, even minor, (work related) she buys me chocolates. She clearly wants to be friends and doesn't get the hint that I want to be professional acquaintances only. If we have a minor insignificant interaction at work she'll message me that evening on facebook, saying things like 'thanks so much for blah blah blah, hope all's well with you'. A couple of times she's randomly driven in next to my car just as I'm leaving work, 'because she needed to tell me my car windows were open', though there's no reason for her to be there. I can only assume she was waiting.
I find her annoying, but harmless, but it does make me feel uncomfortable at times. Currently my approach is avoiding unnecessary contact, being polite when needing to, and not replying to any social media messages. It feels weird ignoring messages but I'm not obliged to interact with someone outside of work if I don't want to do I?! Am I rude ignoring her?! Anyone been in this situation?