Your experiences would be appreciated!

Currently planning a LHR-PEK then NRT-LHR trip next March(ish). Plan is to (in the near future) buy two WTP open-jaw tickets and MFU them to CW for the entire journey. (BAEC tells me there is availability on any day I want to fly, but I'm flexible)

It's a special trip, and I would very much like to fly myself and Mrs Malkie CW there and back. (I know I could just pay for J tickets if it's that important, however that does slightly defeat the point of loyalty to an airline to rack up FF miles)

Neither of us are status holders - although I've flown regularly with BA across the atlantic for the past decade it's never been frequent enough to earn status. My issue/concern is that closer to the time (or on the day of flight itself) we get downgraded to WTP in favour of a status holder or someone who buys a full whack ticket at the last minute.

(Makes for sensible business - I'm assuming BA would prefer to honour the business of genuine frequent flyers / full-price ticket holders).

So, I'm asking of people's experiences with keeping their MFU seats, particularly if they are not status holders. Am I worrying about something which very rarely occurs ?