OP - yes you should be worried as the recent aggressive activity by UA justifies it - but since it's clear that your activity is within the rules I wouldn't worry too much... For example - I just submitted some requests for upgrades for friends with no familial relationships - I was called immediately and confirmed it was me - this is new but when asked how I know the people traveling I simply said its none of their business - and they was fine.... Bottom line is don't worry - you are fine....