Before the workshop, get a sense for the context the team is acting in.
Why Workshops Don’t Work (and What You Can Do About It)
Jorge Arango

This again depends on different factors. For instance I have my *content strategy* workshop scheduled for a University staff next month. I am planning to meet the audience once before the workshop to know the current variables that define their work, thoughts, actions, and outcomes. Meeting (or speaking online) to the workshop audience before the workshop (particularly when the topic is new to them OR when the audience do not know the presenter) always help you define the expected outcome of workshop for big picture goals.