JW's always pick up and run with any information regarding punishment. Ask them an indepth Bible question....you'll usually get a vague answer or blank stare. Ask them about anything to do with Watchtower policies regarding any kind of punishment, they'll know all about it.
Shunning is the only power JW's are allowed....especially for the sisters.
If I were you I'd let it fade....in a few weeks it'll probably be business as usual if you don't make them draw a line in the sand about it, now.