Return Envelope Window ...be sure address shows through window

You’ve seen that a few times. Why is that my problem? If you sent me something and you want a response, thanks for the envelope, but, why don’t you print your address on the thing? First, it costs more to die cut and put in a window. Second, you know 2% of the envelopes will hit the mails with no address showing.

Window envelopes leaving your place might make sense.
The return envelope should be pre-printed. In an inquiry to 14 companies, not one person could explain the return envelope
being of the window variety.