I don't think there is a new stance...as someone mentioned a few months back there was an article that basically said if something no longer had pagan connections it is OK. It's main example was the use of Pinatas and how that is OK nowadays. The article then went on to specifically mention B-Days as things to avoid, so as usual it was quite contradictory.
We were "reported" for letting our kids go to a b-day party, the funny thing is, when the elders met with us, they barely mentioned it. They were more interested in our service time and meeting attendance.