May be in Langar Hall or in Kitchen; we do see ARDAAS and KIRPAN BHET of Langar with Jatha singhs. It is also seen alongwith KARAH PARSAAD (in the Hazoori) though not as frequent. May be it depends on the situation. If Langar is ready, only near the end of the programme and Langar Hall is not far away; then it is convenient to have a single Ardaas. Generally what I see, Langar is ready and Ardaas & Krpaan Bhet is done in the kitchen itself, so that it can be served before the actual SAMAPATI of the prgramme. Veer Ji to please correct the observation.
As regards the relevance of the practice; I think, it is same as of Karah Parsaad.
Recently a friend told me that a hindu priest once remarked that in Harminder Sahib, you (sikhs) bring PARSAAD and take it back for distribution simply after a Kirpan Bhet. You do not present it to your God. He wanted to tell that in the temples, hindus take PARSAAD to the mouth of diety. According to him, this is actual method of BHOG.
We would certainly like to say that our practice of ARDAAS and KIRPAAAN BHET is different and more meaningful than what they do in temples. Anyway, it is sometimes difficult to explain our practice of Kirpaan Bhet and Ardaas to non believers or so defined liberal sikhs also.
Bhagat Dhana Ji was able to see the LORD enjoy the food prepared by him. The sakhi says that, he was given a THAKUR ( A stone as diety) by a priest. Bhagat Ji in his innocence, stopped taking his meals, untill the THAKUR took the food. And the miracle happened. God was there to eat the food.
So it is the devotion, which matters.
In case of Kirpaan Bhet, what I feel, we request the blessings of Guru Sahib before taking the food. Kirpaan is no less than a God for us. It is our PEER. So Guru Sahib, through Kirpaan Bhet, gives us permission and blessings for taking the food. He touches our food. Some may call it a ritual. But this ritual is meaningful for us, as long as we have the feeling attached with it. We have no better way of requesting HIS touch to my food.
This is what I understand from this practice. Not only in case of Langar, I have heard of ladies, who prepare food for the family and do ARDAAS and Kirpaan Bhet before serving it to the family.
Bhul Chuk Maaf Hove Ji.