Can QF first passengers invite Economy to dine w them?

Can QF first passengers invite Economy to dine w them?

No, but you're free to wander to the back and dine next to your friends in economy (note: may also involve eating the economy meal).

Seriously though, Qantas is pretty strict on non-F passengers being in the F cabin, and with good reason. But it's not unknown for them to allow a first class passenger and a friend in economy to share a drink and a snack in the upstairs business class lounge, and that's indeed a nice way to spend some flight time, and even (if it's your partner) watch a movie together.

You could watch Titanic (1997), where that was in fact allowed that one time.

Likewise, I have been in F on QF and asked an FA if I could invite a passenger from Y to join me for a drink in the J lounge, and she immediately asked what we'd like to drink.  When I said Shiraz and my friend said Cabernet, she gave us a full bottle each, and then delivered a cheese plate each.  An hour later she delivered a fruit plate each.  We were both very pleased.

Cam I stood to stretch my legs & back in F on QF on the A380 recently when, seeing me do this, the flight attendant suggested I go for a walk.  Describing it as if a long walk, he suggested a I go upstairs, walk through J and then ask a flight attendant to open the gate behind PE to let me down the stairs at the back and walk back through Y.  A different flight attendant tried to prevent me entering the curtain back into F.  I had to convince her to let me back in, that is how strict they are !!  But, voila, my bed was turned down and ready upon my return :)

No

When I flew QF First recently from Syd to Lhr, the flight attendants allowed a husband (who was in First) and his wife (in Y) to alternate their seats every few hours throughout the flight.  They were never both there at the same time however -  I understand that they had a young child with them on the flight (who stayed in Y). So, in this circumstance, the attendants probably wisely saved the marriage.  I can't imagine any spouse would be too happy to be left with a young child in Y for 24 hours while the other spouse lifted it up in F.   

*lived

Last time in F the FA's allowed a husband in J to visit wife and child in F, although polite having 3 pax in the suite behind me was most off putting. When i phone QF after a post here they expressed the view that ONLY F pax are allowed in F cabin. AS it should be if one is paying over 12k for a ticket to europe.

I wouldn't be too keen paying a F fare and having some other class crash a neighbours F suite for the majority of the flight. They might even want to bring along their cabin bags for an easier departure as well.

sgb I often wonder who pays for an F fare, mine are always redemption tickets.  I had a family occupying 3 seats on a recent BA flight LHR-JFK and wondered how the pre-schooler would behave.  He was delightful but I did (admitedly selfishly) think, if he weren't, that would take the shine of F.

This 30 second Seinfeld clip is spot on about the gulf between First Class and Economy: https://www.youtube.com/watch?v=d2JKXbVGq7A