I'm not sure if it is the exact same tour, but I took a free walking tour of SdC when I arrived there last July. We met in the plaza outside the Parador. It was pretty good. Not quite as exciting as being on the Camino, but I saw things and learned things that I would have missed otherwise.
Thanks so much for this Johnnie. While writing I have to say how much I enjoyed working through your "20 Things To See And Do" list in Santiago back in 2014 - I managed 18 of them and hope to do the remaining two when I hope to be in Santiago in July.
Cheers from Oz -
Pretty sure that this is the same idea as what I just saw in Lisbon a few weeks ago (they had red umbrellas). I talked with a couple of the young guides at the Praca do Comercio and learned that this is a way for unemployed history, art, archaeology, etc. grads to make enough money to squeak by. They are knowledgeable and peppy and hoping to make a living.
So, irrespective of what you think about "tipping in Spain", referring to the recent thread, tips are definitely expected and generous tips are very much appreciated. If this is like the Lisbon operation, these guys get no salary and live off the tips.