Yes there are so many factors which affect detection capability in the field. The amount of air in the soil is one as you say and you will see detectorists avoid freshly tilled soil for this reason especially if it dry. The use of power harrows to make a seed bed often produces this affect when drilling late spring crops such as peas and despite a very inviting field few will bother to search. Frost is another factor with a better response after a good hard freeze. I think these factors still remain as technology can give you more programmes to input plus more value add ons ,but at the end of the day it is often a case of going over an item and even the general run of the mill detector will outscore the die hard professional with his latest ?1000 plus gismo.
I do take your point on organisations which is why such surveys need to have strictly defined conditions as to how they are carried out otherwise the end results can be far from acceptable. Transects have their limitations as broken pots with many sherds will go along way in the ploughsoil whereas a few metallic casual losses will not and so the results from fieldwalking and detecting along the same transects are just not comparable. I find total coverage of selected areas a better method using detectorists who will stick to the requirements.
As for the putative plunderers all i can say is a certain archaeoblogger is making hay with your comment and predictably using them in his usual selective way as if he is trying to prove the world is indeed flat so i will not elaborate and give him more to blog with.
I do take your point on organisations which is why such surveys need to have strictly defined conditions as to how they are carried out otherwise the end results can be far from acceptable. Transects have their limitations as broken pots with many sherds will go along way in the ploughsoil whereas a few metallic casual losses will not and so the results from fieldwalking and detecting along the same transects are just not comparable. I find total coverage of selected areas a better method using detectorists who will stick to the requirements.
As for the putative plunderers all i can say is a certain archaeoblogger is making hay with your comment and predictably using them in his usual selective way as if he is trying to prove the world is indeed flat so i will not elaborate and give him more to blog with.