I think there’s a difference between having a letter read in Sacrament meeting on one Sunday and what happened in our Northern California area: Having multiple talks, firesides, training meetings, sign-up sheets, in-home visits by bishops and stake presidents suggesting donation amounts, recurring reminders about filling out donation forms, canceling important ward/stake activities so members are free to volunteer for the proposition, conference calls about donating, encouraging all RS members to make sure everyone in their families is registered and (as necessary) has absentee ballots to use, and having bishops close Sacrament Meeting the Sunday prior to the election with a special prayer that voters will act righteously and support the proposition.

So, while reading one letter (or even a couple of letters) in SM or RS/PH could be seen/interpreted as low-key encouragement to get involved, the real pressure came from the repetition of the call for involvement.

It would be nice to see the wiki include ALL of the things Mormons were asked to do to support the proposition, starting with the list included in this comment and continuing with the very specific counsel given at the October 9th fireside which suggested the numbers of volunteers needed, the hours suggested, the activities suggested, and the get-out-the-vote, final 100-hours of events, including precinct monitoring.