Put quite bluntly:
Should we (mere mortals) copy details from professional games into our own?
A game of Go is more than a collection of small plays, it should be a coherent whole. Should we automatically assume that we can / should always apply 'professional practice' in our games, where the rest of the game, both before and after is different?
SAS: This page was started in reaction to a comment of mine that professional practice suggests that the correct response to a crosscut is more often an atari than a nobi. My point wasn't that we should follow professional practice. My point was that professionals are very good at reading these things out, and the fact that they mostly atari suggests that an atari is correct more often than not. This is just an interesting observation, not something that we can usually apply in our own games. Professional practice when faced with a crosscut is to read things out, and we should do this too.
But whether or not we should generally follow professional practice surely depends on what sort of professional practice you are talking about. For example, I've never seen a professional game in which the first move was played on the 8-9 point, but I see no reason we as amateurs should not play there --- the surprise value may well make up for the theoretical loss of a few points.
Stefan: My opinion about this is purely pragmatic. I'll rip anything I see, from professional or other games, that seems to work and will help me win games. From a more philosophical perspective, I'm sure you can't progress beyond a certain level without the proper professional attitude and practice. By the time I reach that level (if I reach that level...) it will probably be too late for me to change my ways. Too bad. I know people who are more rigourous in applying pro-like standards from an early stage, but it's too much overhead for me. I'll keep trying to trip them up with my back alley tactics. :-)
Morten I like SAS's comment, I hope he permits me to paraphrase it: Professional practice when faced with a position is to read things out, and we should do this too. As you may gather, I am not necessarily keen on always following what the professionals play (maybe I should be :-) if I feel that it doesn't suit my game - and I don't necessarily just mean local positions, but whole-board approach. Depending on which professionals you refer to, they differ wildly as well. I am not arguing that a professional would lose a match if he played against a strong amateur, but I think that medium amateurs will not necessarily improve much by playing the latest joseki or statistically applying what the average pro plays :-)
Too often I've seen a high-ranked player justifying a professional play with a looong complex sequence of 'forced' moves and an eventual gain of 1 or 2 points. This is not very stimulating for the ooh-ing and aah-ing disciples around who try to play the same play themselves and get hammered in the process.
Hence why I like the '...read things out - and we should do this too'.