I'm fine with being hired help, and I don't see anything "mere" about it. The client hired me because they need help. I make the assumption that they want me, and everyone else they hired, to work hard and get the job done. It's what I would expect if I were the client.
I've had clients invite me to sit down and eat with them and their guests, and I've had clients that never mention anything about eating. I wouldn't go into a separate room to eat, but that's because I usually don't eat when I'm shooting weddings/events, and as hired help who needs line-of-sight to get the job done it would make me nervous to be away from the action. I'll grab water, and some caffine, and maybe a quick snack I brought myself, but I'm definately not a guest or participant of the wedding, so I don't expect them to set a place at the table for me. I know that some wedding photogrpahers put the meal, and where they would like to sit, in their contracts.
At a recent wedding I was appalled to watch the DJ voraciously shoving shrimp coctails down his gullet, making grunting noises, facial expressions, and everything, between playing songs. That guy made 20 trips to the buffet, ate for 2 hours straight, and padded his salary with his own body weight in seafood. As a wedding vendor I was sort of disgusted and embarassed. As I was leaving about an hour before the reception ended (I work by the hour, and had received the okay to split from the bride), he had the gall to chastise me for leaving before the end of the reception. I felt like telling him off, "I've been with the couple since this morning working my tail off. You showed up 2 hours ago, and you've got coctail sauce splattered all over your face and your CDs."
On commercial shoots we almost always take a lunch break, and about half the time the client buys me lunch, although I wouldn't expect it. To be honest, I'd rather skip lunch, and just be done with the job an hour early.