Personally, I really admire people who earnestly put their intentions and feelings out there. I find that a lot of people find it a real challenge to do this. I think if someone pursues you, and you don't think it's right, out of respect and honour, something should be said and/or explained. Even if its simple 'I don't see you that way'.
If you don't know where someone is at with themselves, I think it's a good idea to give them a piece of 'closure' if that's the right word for this context. I think putting yourself out there is an emotional investment in itself and people need some sort of soft landing.
In saying that, a couple of years ago as a new convert, I remember I was working at the auto parts and accessories retail store on weekends while studying at university, and this really nice young man asked for help with parts for his car. He was really confident and kind. He left, came back, I made some joke that left both of us cackling with laughter, then he came back for a third time asking for my number. I was super excited. So we said we'd meet up for coffee at night since I was still working at that point.
So while I kept working, he messaged me 5 times and called 5 times, and then started leaving messages like, 'Leaving me hanging, you're so mean.' So the red lights start flashing, I felt very uncomfortable considering he knew I was working until late afternoon. At first I didn't respond, but eventually he called again and again, and I just ended up messaging him, 'Sorry, I don't think this is a good idea. I'm sorry about this.' I just felt like I needed to let him down gently because his emotions and reactions did not seem stable, which was such a contrast to the man that asked my for my number earlier that day.
And actually thinking about it, he may have been the last person who actually took the first step and asked me out for coffee. Wow, it's been a long time.
... Maybe... I smell bad or something....? Or maybe because I love tacos too much.