As you can see in the comments on this post, the lady who hugged me was actually the great auntie of the baby who was being visited. I did end up leaving a thank you note (laminated of course) with my name and the address of my blog. I am so grateful that it wasn't taken the wrong way. I wasn't quite sure if I was being rude or not. Maybe someone else may have taken it differently.
Okay, even though the issue's over now, I think I should share what happened the day I left the note. As I pulled up to "our" spot, I noticed there were some workers doing something in there - cleaning up the dead flowers and such - two older men and one around my age. The two older ones left the area not long after I parked my car, but the young one stayed. I kinda smiled at him in that "yes, I see you, but can you please leave me alone" kind of way as I put the note down and then moved across to Ianto's grave. He was still there when I looked around again. I started to feel a little uncomfortable.
A few minutes later, I got a little bored (yes, I admit it, I have a really low attention span when I'm visiting people's graves, even Ianto's) so I looked around to see if I could clear anything up on the other graves (another habit of mine - I'm always straightening flowers or picking things up that were knocked over)... The guy was still there. But worse. He was not sitting between two babies' graves, smoking, and staring at me as I went about what I was doing. I felt so horribly uncomfortable. Usually I'd stick around in there for 15-30 minutes, but this guy was really creeping me out, so I left. As I got close to the gates of the cemetery, still thinking about it, I decided to go and make a compaint to the office. The lady there was so nice, taking my name down and telling me they'd get back to me the next day.
When they did get back to me, apparently this guy had been given a real talking-to, and was willing to apologise face-to-face. I never want to see him again (I feel that violated) so I said it was unnecessary. They also informed me that it's in their policies to move away from the graves if someone comes to visit (hence the two older menwalking away when I pulled up), it's strictly forbidden for them to smoke in the public areas (let alone the children's area), and it will be brought up at their staff meeting next week. I'm quite happy with that result.