[PvK]

The rate or marking is quite low, but will happen to some lantern researchers eventually. But then the chance of getting attacked is also I think pretty low. So generally it is not a concern - as Cor wrote, just don't give them to particularly important mages. It would probably just call a lesser horror, which could be escaped with a few bodyguards or an escape spell or a good offensive spell, but except for spells it's probably not worth protecting them given the low odds of it happening.

It could potentially end up being a setback if you switch those researchers to battlefield mages at some point, and the enemy uses Call Horror or something... but again, the benefit probably outweighs the risk by a lot.

As MA Ulm, I think lanterns are very worthwhile to use.

PvK