I think we'd have to break it down more to clarify what exactly an 'Invoked Crossover' actually is. For instance in 'The 'Three Magical
Knights' its not a crossover so much as Carrot and Dan LARPing in elements of Slayers to screw with things... and Carrot was following Dan's lead if I
recall correctly. 'Insertion: Reflux' Carrot picked elements and inserts to screw with a random Ranma and then seasoned to amusement. In Gaijin, the
SI is actually warping reality around him by making random choices (like using Spiderman as a cover identity)... who is apparently using the same method that
the (Sailor Moon 1st season) Greater Big Bad used to become the Greater big Bad in the first place. Only he doesn't really know why this is happening,
kind of like .a certain Melencholy character that has the world out to get him and is aware weird things are occurring... and the are hostile. 'A matter
of force' appears to be a character that is psychical picking up on crossovers before they come into play. Insertion is a mixed bag of cHaoS.
So to be a trope we'd have to actually be rather specific on what the trope in question is based on in the first place.
Knights' its not a crossover so much as Carrot and Dan LARPing in elements of Slayers to screw with things... and Carrot was following Dan's lead if I
recall correctly. 'Insertion: Reflux' Carrot picked elements and inserts to screw with a random Ranma and then seasoned to amusement. In Gaijin, the
SI is actually warping reality around him by making random choices (like using Spiderman as a cover identity)... who is apparently using the same method that
the (Sailor Moon 1st season) Greater Big Bad used to become the Greater big Bad in the first place. Only he doesn't really know why this is happening,
kind of like .a certain Melencholy character that has the world out to get him and is aware weird things are occurring... and the are hostile. 'A matter
of force' appears to be a character that is psychical picking up on crossovers before they come into play. Insertion is a mixed bag of cHaoS.
So to be a trope we'd have to actually be rather specific on what the trope in question is based on in the first place.