In what scenario can a lay witness not become familiar with a signature solely for the purpose of testifying?

A lay witness cannot become familiar with a signature solely for the purpose of testifying when testifying about the signature's genuineness. The rationale behind this is that lay witnesses must have personal knowledge that allows them to provide testimony. Familiarity gained for the sole purpose of testifying—such as being shown a signature immediately before giving evidence—lacks the necessary foundation of familiarity from prior knowledge or experience. In this context, the genuineness of a signature implies authenticity which requires the witness to have had earlier and consistent exposure to the signature outside of the courtroom context.

In contrast, a lay witness can have seen the signature in the courtroom, which establishes a minimal basis for opinion testimony. Familiarity in daily life offers a solid foundation for recalling and positively identifying a signature, and being shown the signature through a process could also establish recognition as long as it is not the only exposure. Thus, the context of genuineness specifically necessitates prior familiarity, rather than the brief acquaintance formed solely for the purpose of testifying.