I've seen the same thing at most Marriott/Hilton lounges. I don't think there's any rule that you have to remain in the lounge to eat or drink unless it's liquor and their license requires you to consume it in the lounge. (Even that is rare, I think.)

I commonly drop by the lounge at whatever hotel I'm staying in to grab a bottle of water after I've gone for a run. In the mornings, I sometimes grab a water and a banana to take with me for later in the day. I've even seen hotels provide little brown bags for people who want to take a bagel or fruit with them.

But anyway...back to the original topic of the thread:

(1) I've never seen breakfast poaching at any of the roadside motel brands mentioned in the OP. Seems like a poacher would have to be pretty gutsy to drive up, park, walk in, and start chowing down. Furthermore, why? It's not like those places are serving up caviar and Cristal. Others have speculated that it's the thrill of something for nothing, but is it really all that big of a thrill? I think I'd be thinking "I'm poaching a crappy motel breakfast. This isn't really all that fun - or all that tasty." So I suspect it's a fairly uncommon practice.

(2) Inviting a caravan into the executive lounge with you. This I *do* see on occasion. At least, I suspect it. I usually see it in the form of a full-on business meeting taking place in the midst of the lounge. OK, perhaps a chance that everybody is Gold or everybody booked rooms on the C-level, but still I suspect there's some lounge-sneakage going on. I stay at Marriotts often with coworkers who aren't frequent Marriott guests. I usually don't even mention the C-lounge to them - if I want to meet up with them for beers, I meet them in the hotel's main lounge.