I haven't found anyone living yet (well except on GR). However, I think including a few trees of your research would be very helpful. If it is the right person, I think they're more likely to reply if they know that you ate are (what a typo!) a relative. I have been considering contacting living relatives. I have found a few deaths for siblings of my G Grandfather which are reasonably recent, one of which was only 5 years ago. I have considered ordering their death certificates to get addresses.
However, the way I see things is that if you don't jump at opportunities you get, you can end up regretting them. If you decide to do this 5 years down the line, the person you were trying to contact may not be living anymore and information would be lost. Also, there is little harm in contacting someone - even if they don't reply, you have not lost anything because you never knew them in the first place. However if they do reply and do send you copies of photos, information etc then it will have been a brilliant success.
My advice: Take the opportunities you get and there's nothing to lose by contacting someone. I wish I took heed of my own acdive sometimes.
Andrew