[Avodah] May Kohanim visit the Rebbe's Ohel by means of a "box"?

[Zev Sero]

Moshe Y. Gluck wrote:
>> R' Richard Wolpoe wrote:
>>> Rav / Herschel Schachter states:  /
>>>  [...]
>>> And now by extension may kohanim use an innovation such as a box to
>>> visit the Rebb's Ohel?
> R' ZS: 
>> Why on earth not?   What issur are they doing?
> 
> Would someone kindly explain the Metzius of the situation? The Gemara talks
> about Ohel Zaruk, and boxes, so I assume that there there must be something
> else here that makes R' RW raise this question.

A cohen may not come within 4 amot of a grave unless there is a mechitza
between them.  The path leading to the LR's ohel is quite narrow, certainly
less than 8 amot wide, and lined with graves; therefore an unassisted cohen
may not pass through.  The solution is to create a mechitza between him and
the graves.

The way this used to work was that a group of people would gather around
the cohen, forming a mechitza around him, and the entire group would walk
together.  A mechitza made of people is 100% kosher for all purposes - 
even on Shabbat, such a group may parade through a reshut harabim, with
the person in the middle carrying.  (On shabbat, the people must not know
for what purpose they're being gathered until after the mechitzah has
formed; once they're in place they can be told that they are now a kosher
mechitzah, and to please stay in formation.)

Then someone came up with the idea of providing boxes, which consist
of four walls with handles in the middle - the cohen steps inside the
box, lifts it up by the handle, and carries it with him; the box forms
a mechitzah all around him, and he can go past graves without a problem.

AFAIK all of this is 100% lechatchila, and doesn't rely on any kulot
or heterim.

At the ohel itself there is a mechitzah of 10 tefachim around the
graves, and no roof over them, so there is clearly no problem.

-- 
Zev Sero               Something has gone seriously awry with this Court's
zev at sero.name          interpretation of the Constitution.
                       	                          - Clarence Thomas