Do atheists get offended when someone of faith prays for them?

If someone of faith prays for an atheist does he/she get offended? Or is it the mere knowledge that they are being prayed for the reason for being offended? It is possible atheist are being prayed for this very moment but they do not know it. Since prayer never harmed anyone, why would he/she be offended of getting it? I have my theory but as to not make it about what I think, I will leave it generically as to why you believe.