The exchange of sealed envelopes

From The Strategic Review (Spring 1975):

Although it has been possible for enthusiasts to play solo games of DUNGEONS & DRAGONS by means of “Wilderness Adventures”, there has been no uniform method of dungeon exploring, for the campaign referee has heretofor been required to design dungeon levels. Through the following series of tables (and considerable dice rolling) it is now possible to adventure alone through endless series of dungeon mazes! After a time I am certain that there will be some sameness to this however, and for this reason a system of exchange of sealed envelopes for special rooms and tricks/traps is urged. These envelopes can come from any other player and contain monsters and treasure, a whole complex of rooms (unfolded a bit at a time), ancient artifacts, and so forth. All the envelope should say is for what level the contents are for and for what location, i.e. a chamber, room, 20’' wide corridor, etc. Now break out your copy of D & D, your dice, and plenty of graph paper and have fun!

The idea of exchanging envelopes amuses and inspires me. Did players actually do that?