I think it would be fine depending on how often it's given.
I think the quality of the lunchmeat might help too...like I know at times if we have sliced turkey we'll offer a bite to the babies, but it's not a daily thing or even a weekly thing for us, so I figure it's ok.
I think if it becomes habit and starts interfering with their regular food might be the only thing to worry about.
I think drjean has an article with a list of foods that are harmful for them, but I'm not sure and am on my way out the door to work, so not able to check right now! I'll check tonight when it slows down at work and if it's not posted, I'll see if I can find some links for ya!
Btw, don't take my word for it on this! I could be completely wrong!!
Probably, might want to use fresh (like sliced from the deli counter) meat too. I believe that some of the prepackaged ones have a lot of preservatives and yucky stuff in them, that we should be avoiding also!