I think the puja in question is the "Grand Prayer that Blesses
and Benefits all Sentient Beings", or "水陆法会“ in Chinese (literally
means Puja of Land and Water). Its tradition dates back to Liang
dynasty, when it was commissioned by Emperor Liang"
See
http://media.kmspks.org/uncategorized/water-and-land-great-festival
and in Chinese
http://baike.baidu.com/view/49829.htm
The puja is a very large scale one. The whole ceremony lasts 7
days and 7 nights of chanting of various important texts, and is
divided into 7 altars or shrines. There is an inner shrine and 6
outer shrines, and they require 59 Bhikkus to lead the chanting in
all 7 shrines. Other helpers are needed to help out with reception,
cooking, admin, etc, and close to 100 people in total are required
to organize such a large scale puja. Furthermore for the puja, for
all 7 shrines, there needs to be many offerings such as oil lamps,
flowers, fruits, vegetarian food, etc, and need to be replenished
everyday for 7 days.
The cost of organizing such a grand puja is huge, considering
the costs of tentage, the large amount of offerings required, and
the amount of manpower involved. Typically (and historically), the
cost of all 7 shrines are borne by a few sponsors from the laity
for benefit of everyone who wishes to participate in the
puja.
The reason why the inner
shrine is restricted to few people is to minimize interruptions
from having too many people moving in and out of the shrine, as the
chief master presiding over it has to perform complex
visualizations during the puja and requires full concentration.
That is why only few people are allowed in the inner platform, and
for expediency reasons only sponsors are allowed.
The outer shrines do not have
such a restriction and people are free to attend them to dedicate
merits to the deceased or to their families and friends. The outer
shrines are free because of the donations of the sponsors. There is
no difference in merits accrued from the outer or inner
shrines.
Of course, one way to avoid
misunderstanding is to disallow anyone into the inner shrine other
than the presiding monks. But that also defeats the purpose, as
most people (sad to say) would not want to sponsor the puja if
there is no such privilege. So out of expedient means, and to be
able organize the puja to benefit all sentient beings whether they
have the means to sponsor or not, the tradition is to allow just
the few sponsors into the inner shrine. This achieves two goals: to
minimize the disruptions in the inner shrine as explained earlier,
and to be able to conduct such a large scale puja to benefit all
sentient beings.
Btw, I am not affiliated to KMSPKS, but just wanted to provide
some background information so that everyone can understand the
context better.
Thanks for the info.
and links. Hopefully it will help to clarify why certain religious
event needs restriction to be put in place on devotees attending
the event at KMSPKS monastery.