This was the first players had heard of adverts being inserted into their voice chat and speculation began to run wild in the game's pre-release forum community. Players feared the worst -- that right in the middle of their game, a radio advert would start playing over their speakers. Community Officer Toxico was quick to address concerns, explaining the exact circumstances under which the ads will be played. For an advert to play, you have to be entering a district and must not have heard an ad for the past three hours. This ensures that they'll never interrupt normal play and won't play in an irritatingly high frequency. While some forum posters are avidly opposing a premium VOIP service, most seem content with the explanation provided and the conditions under which adverts will be played.
[Thanks for the tip, Kip!]