Personally I feel there are and have been "abuses" of SC promos - of course it all depends on your definition/idea of the word "abuse" in this context.
eg if I book and fly 10 trips under DSC that earn me, say 2000SC vs 1000SC that I might have done is that an abuse? Even if it gets/retains me Platinum status? Is it an "abuse" if one uses DSC to push themselves to P1 when they normally wouldn't make it? I don't know.
QF don't make these offers without doing the cost/benefit analysis on it (ie "running the numbers") - they know people will use these to keep or up their status levels. Probably a small number on the grand scheme of things and they probably feel they can wear that "cost"
Remember with SC promos, you're still giving QF revenue and I think most of these promos, bar the April global one this thread is about, are a) targeted and b) very limited in application as a tool to raise revenue to QF in the short term, and as a tool to help retain/reward(take your pick) loyalty.
Probably the biggest "cost" to QF would be those going from MB or PS to SG and WP as it's a whole jump in perks from Silver to Gold but remember even for those that say gain status levels via SC promos, one still has to fly (ie: provide revenue to the airline) to use them so there is still an ongoing effect to QF to provide that status. Even if one goes from NB to WP but then basically flies twice a year as a WP the cost to QF is pretty little, and if they fly more than they did as a Bronze, then QF gets more revenue for that outlay.
Sure, this promo I have used through selective bookings into my new membership year to fast track me to retaining P1 for another year. Is that an "abuse"? or is it, as I call it, "taking advantage" of the (very rare) promotion. End result is QF still gets a bucket load of revenue out of me either way. I don't think they're losing too much sleep over it, and my PCV I guess would go down on the basis of yield/SC or whatever their metrics are. They know what we spend, and what we do.. it's the whole point.
Let me put it another way.... does doing multiple PTV runs (before the end of the year anyway) on AA to get "cheap" status also constitute "abuse" of the system? or "taking advantage" of the policies and provided benefits? It's not for me to say I guess we all have to make our own value judgements on the matter but I bet you anything there are folks at Mascot cheering AA's decision to move those domestic sectors out of the A and P buckets to D and I.
I suppose at the end of the day one could suggest it's all about "intent" - both the intent of a promotion or program rules and the "intent" of using those. If I book extra trips under DSC even if they're pure runs (I may have one coming up in a week or so
) it's still revenue. QF still gets a handy yield out of it. Is my intent to abuse the system? no, my intent is to make the most of a very generous offer (as we all have).
I do consider things like the "Baht Run" guy back 15 odd years ago to be an abuse (for reference to those that don't know this story, it was a guy who basically subcontracted cheap flying in Thailand to locals to fly multiple rountrips a day earning him UA status at a rate of nots - enterprising for sure - but clearly an abuse of the system-because it wasn't his bum in the seat for one).
Bottom line if QF considered the status runners "abuse" of the system they could add any number of restrictive clauses to both promotions and general T&C to prevent this kind of thing. They don't (yet), or they feel the "spill" is small enough relative to the huge FF base to not be an overall problem. I don't know, I am not in QF Loyalty. For me, I see no issue with using a promotion offered by the airline as much as I can and I don't think it's an abuse of the system if it's within the published rules of both the promo and the overall program. YMMV
happy flying!