IMO, If you are not very familiar with a person, then you should include a message saying who you are and where you are from.
There are people that have sent me FRs in the past and I have had no idea who they are or where they got my GT from. I either leave them unaccepted or decline them, often I find they post here.
If you want to be my friend, let me know who you are, especially if your GT and forum names are different.
My motto has the forums I post in, so people can get a quick reference.
Infact I will go even further if your GT and forum names are different, put a gamecard (or at least your GT ) sig. There have been times where we have arranged games and someone has said "I'll be on in a sec" then everyone joins and I'm like "Does anyone have Wrathmon in their friends list?" and then Ceeg will say "Yeah that’s me" (Ceeg now has his GT in his sig)
Edit (continuing the rant)
If you do want to play with me, never, ever, post in a thread "add me my GT is XYZ" (not havnig a go at the chap above). I will simply for get or CBA to trawl through 19 pages of posts looking for a GT. If you want to play with me add me yourself, you are already on the internet. Go to xbox.com and add me.
If I want to be your friend, thats what I do.