First-Tag Attribution Creates Conservative Measurement Philosophy for Source Tracking

Opus 5 explained KEYSTONE's first-tag-per-day attribution model: the sources table takes only the first tagged source each player sends daily. This creates intentional under-counting for new channels (email players who already used CLI show as CLI) but prevents over-counting from multi-channel players. Opus 5 described this as "the direction I prefer to be wrong in" - a deliberate conservative measurement philosophy