[CQ-Contest] A question of protocal

[Clint Talmadge]

As a casual contester I have some questions. 

Recently when the Reflector was asked how to contest from a small city lot one of the answers was "Get a friend out in the country".  In addition to that, occasionally K1TTT will offer the use of his station.

Also I have seen contest results that list call signs, such as "W1ABC (K1XYZ op)" and "K1XYZ at W1ABC".  The assumptions are that the first is K1XYZ operating W1ABC's station and using his/her call and the second is K1XYZ at W1ABC's station and using his/her own call.  


I pondered both of these and wondered.  When using another's station, which call do you use?  Is there an established protocol for this or something that is worked out on a case by case basis.

Thanks,
Clint - W5CPT