Signal can leave metadata (phone numbers) behind whereas talking in person doesn't usually unless some comms were used to suggest it, security footage, or cell

Signal can leave metadata (phone numbers) behind whereas talking in person doesn't usually unless some comms were used to suggest it, security footage, or cell phone pings were to allude it. I'm wondering if evidence of a conversation occurring can be used in a legal context as circumstantial evidence or to suggest suspicion or intrigue.