Actually, don't we talk all the time on here about how a hostess gift need not actually be served at the party, i.e. you don't have to open that bottle of wine someone gave you as a hostess gift? There's a difference between a hostess gift and a dish for potluck, and this was the former.
For me it is strange because it is a Super Bowl Party, which in my experience is not at all like a formal dinner party - more of a smorgasboard or potluck type feel, regardless of who supplied the food. That's why I find it strange in this instance (and why I said, "I also think it is quite strange to bring food to this type of party and then expect it not to be shared at the party.") Otherwise I agree with you!
She makes delicious cheesecakes...everyone loves her cheesecakes and she brought a small cake for me and DH as a thank you for throwing a party and providing all the food and drinks. If you want to think she's strange and/or rude to do so, go ahead. She's a good friend and I find no fault in her for doing so.
As for Robert, like I said, it doesn't matter to me what his motivations were, innocent or otherwise, for going into my refrigerator and taking the cake out. I'm not going to prosecute him. I don't know him to invite or not invite to future parties. I may be disappointed that I didn't get the cake that Janet made, but that's pretty much where it ends for me. My question was how to communicate to Janet that I want
her cake without making her feel obligated to go to the extra time and expense to replace the cake....and many people have answered that wonderfully.
While I see no values in the theories of how Robert may have been innocent, I don't mind them being thrown out there. It doesn't change anything because we were never going to 'punish' Robert to begin with. I would even let him come to a future party if his friend asks to bring him again. As a matter of fact, I didn't even tell the guy that brought him what happened. It's done.