Don't worry. Yes, CIC mentioned not to write anything in return envelope. But in case if you write it, nothing to worry. I read, in this thread that someone did the same way and still got his Passports with COPR.miuonpak said:I just sent my passport last night. The girl at post office told me to write down my name and address on the Xpresspost return envelope. I'm not sure if i was supposed to do that coz the PPR email didn't mention anything about it. Did you guys write down your addresses on the return envelopes?
All the best.