This design evolved from being requested by event managers to have the on-site people wear it, to an unofficial uniform, people wore this in the office quite often.
It was introduced at this event, you can find a post here -> https://claudiu.cvrj.ro/stefanini-emea-kickoff-conference/
The “Yes, we can!” tagline was introduced at an event, the same when these tshirt have been brought to light for the first time
