Over the last 12 months I have combined both directions around 300 to 400k, redeemed , cancelled, been refunded, bought extra avios, redeemed again .( all for legitimate family reasons)..all the while fearing that I would trigger an algorithm that would freeze my accounts. Fortunately it was all OK and we have now completed our flights successfully. Have just moved 100k back to BA to redeem for flights for my sister ( who is on my friends and family list and who I have redeemed before) but every time I read a story like this, I do get worried.