Okay, then, that’s just weird. To me there’s obviously not enough information in a text message to tell sarcasm that way. Even a voice message wouldn’t be enough for someone who didn’t know Mark, like the restaurant manager.
I can’t really imagine myself in this scenario any more. My takeaway is that some people are dumb about text messages (or were in 1994 before the smiley).
I’d have to hear the voice mail message to believe what you’re saying. In my daily life, when one of my friends says, “That’s great. Just great” it’s totally clear whether he’s being sarcastic or not. Because he intends to sound sarcastic, and changes his inflection.
Now in this case the message was the same, so the inflection didn’t carry any content. But the subjects were told Mark was leaving a message for his friend. So it’s a reasonable assumption that Mark is using an inflection that his friend will recognize as sarcasm. I would assume that unless, as in the second case, they told me he was trying not to show sarcasm.