Regarding some marriage rituals...of tamil iyers..
I am sure janavasam or whatever it is and kashi yatra are not part of any vedic ritual.
Mangalya dharamam is also a debatable ritual. it is not a vedic ritual.
In The nambuthiri marriages it is the father of the bride who ties the thali.
Thali represents just mangala devata or pratisara devata.
And manalyam tandunaanena etc a much touted thali kattu mantram is not from any veda.
The kanyaka us the property of her fathers kulam and the groom has no authority to touch or even see the girl before the father or the representative of his kulam offers the kannyakadhanam.
Now photos and videos with th groom and bride in compromising positions are made even at the time of betrothal..
But these are boisterous practices over which it is for society and community to ponder over and decide.
The role of vadhyar as a professional is just to conduct the vedic and dharmic rituaĺs.
Of course any vadhyar is a part of brahmin community and that way he can express his views
Panigrahanam at any stage after kanyakadhanam would make sense but holding hands at the culmination of kasi yatra which precedes the dhanam is anacharam violative of scriptural provisions. .