People were not willing to have their pictures taken when we were travelling through Ecuador. Did you find that also in Guatemala.
With many of the indigenous peoples I did encounter this. I did have to pay a dollar or so for ones I really wanted...then there was always using my telephoto zoom surreptitiously.
IMAGE LINK: https://flic.kr/p/EX7pKT Semana Santa in Antigua, Guatemala by Phil Marion, on Flickr