In the Skanda Purana there is the following description of the result of seeing aratrika (worship) of the Deity:
"If someone sees the face of the Lord while aratika is going on, he can be relieved of all sinful reactions coming from many, many thousands and millions of years past. He is even excused from the killing of a brahmana or similar prohibited activities."
As we have already explained, there are different ceremonies to be observed, such as the birthday of Krishna, the birthday of Lord Ramachandra, the birthday of some prominent Vaishnavas, the ceremony of Jhulan-yatra with the Lord sitting on a swing, Dola-yatra (the Lord's activities in the month of March), and so on.
In all festivals the Lord is seated on a car, and the car moves through different streets of the city so that people may take advantage of visiting the Lord.
In the Bhavishya Purana it is said: "In such a ceremony, if even a chandala [dog-eater], simply out of curiosity, sees the Lord on the cart, he becomes counted as one of the associates of Vishnu."
Regarding Jhulan Yatra Ceremony, during these five days the Deities' clothing should be changed everyday, and there should be nice Prasadam distribution and Sankirtana as far as possible.
If you are able to do it, a nice throne may be constructed on which the Deities can be placed. This throne may be swung gently during Kirtana. That will be very good, and surely the Deities will enjoy the function.
———–Srila Prabhupada letter 1st August, 1969