I also usually use self serve so I'm not holding up the checkout queues and draw attention to myself. There's never usually been much supply so have never bought >20 in one go. Have noticed the restocking is more generous now no doubt as demand has been increasing.I just try and only do a few at a time at manned places in case it holds up the queue.
The odd manager makes it sound like you're breaking the law by buying them using gift cards but all their polices and rules are inconsistent.
I just try and do the self serves and be as discreet as possible
Went for gold today and cleaned out as many as I could (I did split it up and do 2 trips at the second Woolies I went to) so I wouldn't need to do so many trips to convert my eGCs to Visa1's.
I think I just got unlucky at Big W, there's always someone who is over zealous at demonstrating their vigilance to management at how good they're doing their job (am I being too facetious here?).
Until they change the systems, it will be fine. Hopefully not for a long time.