Multiple PM recipients?

My PM 'Compose' page used to say I could send to a maximum of 5 people but now, although it still says "Separate multiple user names with a comma", it says I can send to only one person.

What gives?

The maximum was reduced to one person around a week ago to try and minimise an issue with a PM spammer. I'm unsure when the maximum will be returned to 5 people - hopefully fairly soon.