BA Upgrade policy ?

Yesterday afternoon I heard from my friends who were flying to Denver.They were very excited as they had just learnt, prior to boarding ,that they had been given a free upgrade from World Traveller Plus to Business. Just now she texted me from Denver to say that in fact she had been upgraded to First !
Now they don't belong to the Executive Club. The last time they flew BA was 2 years ago. They hadn't even bothered to spend the £25 to check in early to get a good seat- they just did it online 24hrs earlier.
So does anyone have any thoughts as to why this wonderful piece of luck came their way ?! I mean I can't believe there weren't any frequent flyers onboard - or people in Club to be upgraded.
A very puzzled hiljil

When my wife went to Denver last month she, as she does from time to time for business, she was in Club World J but on the return in First. Well it wasnt realy First as BA fly a three cabin configuration to Denver (WT, WT+ and Club) but the plane was a chnage to a four. Although she sat in First cabin it was infact J service without any of the frills; the whole First cabin was infact an extension on J with upgrades and Club was therefore fill of W and Y (Y being a much smaller cabin in the 4 config).

How your friend got upgraded was simple - all WT+ would have been upgraded to Club and as the First cabin had been "downgraded" to J it wouldnt have mattered where the agent had sat them - just needed to fill the re-config plane asap.

Hec I remember this happening to someone on here who wrote about it in a TR

They were moved up a cabin (as were lots of other people) but got the same service as they would have had in the original one - food etc - except they got the better seats!

This route is normally operated as a three class service. Sometimes if a three class aircraft is not available a route can be operated with a First class cabin but with the normal Club service.

Perhaps your friend was fortunate to be upgraded to Club (not surprising if World Traveller was heavily oversold and there are few status passengers on board) and was seated in the First cabin but with Club service?

This route is normally operated as a three class service. Sometimes if a three class aircraft is not available a route can be operated with a First class cabin but with the normal Club service.

Perhaps your friend was fortunate to be upgraded to Club (not surprising if World Traveller was heavily oversold and there are few status passengers on board) and was seated in the First cabin but with Club service?

How bizzarre I think that is what both Mr Tonty and myself have just said in above posts !!

Not checking in early AND being the right people innthe right place at the right time.... (that helps for an upgrade).

We have been upgraded from Y to J on BA (DEN to LHR), Y to J on VS (LHR to LAX) and J to F on UA (both outbound LHR to LAX and return LAX to LHR!). No status on any of those airlines at the time....

Frequent flyers may like to think that everything is done "by the book" by status, but actually it is generally more likely that a class of travel is full and a check-in supervisor spotting an individual or couple that they consider "suitable for upgrade" and...

There was a tremendous post on Flyertalk about what a gate agent has to go through wrt upgrades to get a plane to leave the gate. When it's down to the wire, they will go through pretty much everything to ensure an on-time departure. WHile the BA Denver flight has the situation described above, in general things can happen to make for a one time bonus. It's nice when it happens!

Thanks for all the replies. I have summarised them for my friends who are hoping to duplicate the "magic formula" for their return trip !!!
kind regards
hiljil