Hmmm.
1) They just want to keep some bees for stinging.  
I'm assuming then that they are not beekeepers of any sort.

2) They will be trying to confine bees to a nuc box, year round.  
That's difficult even for seasoned beekeepers.

3) The couple lives in one of the 5 boroughs of NYC where beekeeping is
discouraged.
STRIKE THREE!  This is simply a BAD IDEA!  Tell them so!

Having said that, queen restrictor?  Get a closed nuc box (one with a
hole drilled in the front for access/egress, cut a plastic queen
excluder to the proper size and insert it so the queen will be
restricted to one or two frames with no access to the entrance hole.
This will restrict brood rearing to one or two frames and might keep the
population down sufficiently to thwart swarming.  Then again, nature
always finds a way.  Didn't you read _Jurassic_Park_?

OR

Get two nuc-size brood boxes that can be rotated on top of the nuc box.
Allow the queen full access.  When the top brood chamber is populated
with bees and brood, take it off and replace it with the second nuc-size
brood box and make a new nuc out of the removed populated nuc-size brood
box.  Of course, this will take beekeeping skills to assure that the
queen remains with the original nuc, and moving the removed top nuc-size
brood box will require an additional top and bottom (a cardboard nuc box
could fit the bill here, which could also negate the need for a second
nuc-size brood box).  Just take the 5-frames out of the top nuc-size
brood box and insert into the cardboard nuc box, replace the removed
frames with foundation frames and cart the cardboard nuc box away.  This
still requires beekeeping skills which I assume the couple does not
have, in an area where beekeeping is discouraged.

So no matter how you look at it, this is simply a BAD IDEA!  Tell them
so!

Aaron Morris - thinking good neighbor beekeeping!

******************************************************
* Full guidelines for BEE-L posting are at:          *
* http://www.honeybeeworld.com/bee-l/guidelines.htm  *
******************************************************