I understand what he is asking now (duh). I was thinking in regard to pitching and not to transfer, so yes, I believe aerating and then letting the beer sit for days prior to pitching would be a bad thing in the long term since the oxygen introduced during the aeration could cause detrimental staling.
Now since someone mentioned HSA, how about a data point. Often we here people discuss HSA pre-boil. Well one day last year my spigot began to break on the tun and was drawing in air during the runoff. When I noticed the foam from the aeration was about half a converted keg in depth. My first thought was to stop it and then I thought it might be interesting to let it ride, boil, cool, ferment, etc. and determine just what staling effects had occurred. So the first keg drained pretty quickly without adverse effects. The second is STILL hanging out and has no indications of oxidation. It's over a year old with diminishing charateristics due to age, but no oxidation. FWIW it is a Gotlandsdrika ~1.050. So, IMO, pre-boil HSA is not a concern - YMMV.