Tiruvannamalai pilgrimage donation - genuine or scam?

This happened just now - a group of 4 swamiji s (tambrams basically), knocked on our door, all dressed up in panchakacham and rudraksha mala and said they were taking up pilgrimage to Tiruvannamalai for Karthika deepam. Immediately i understood, they were seeking donation. Now despite being religious, i do not encourage this door to door canvassing, like annadanams, temple building, most importantly the Saai baba thallu vandi donation gang. But they looked genuine so i gave a hundred bucks. They chanted some mantras for me and my family for 2 mins, and then said - they were a group of 16 people going on this pilgrimage from West Mambalam to Tiruvannamalai and insisted that i should donate more. They repeated this for a second time, saying i should contribute amount for atleast for 1 person's meal. I was slightly taken aback and did not know how to respond. I had a bad experience in the past for an orphanage donation gang. At that point they understood and said ok we will not compel you and moved on to the next house. My question is: Is this genuine? the swamijis seemed authentic and their veda chanting was OG stuff. Why would someone from Mambalam come all the way to Velachery and do this door to door collection - all the while its raining cats and dogs here? Why push people to donate beyond what they genuinely offer? have you faced situations like this and what happened?