What is the nature of these calls? Who is calling and from what number? Are they in any way suggesting which way to vote on anything?
Why, after all these years, would they care whether we vote or not (other than to achieve a quorum)?

The only viable answer must be that finally there is a vote to be taken which the BoD cannot this time ignore, and they desperately want that vote to be FOR a reverse split. It is quite possible, and maybe even a little prudent, that they already have the paperwork ready to authorize the resulting extra shares and also maybe have one or more buyers lined up.
I can think of no other reason to hit the phones. If the motion to Reverse Split fails then any contingent business actions fail with it.

A vote to approve the Reverse Spilt may be the last vote you will ever be asked to make.
A vote AGAINST a Reverse Split should retain existing active shareholder involvement a little longer.

CAUTION: PLEASE seek advice from your CPA or Tax Attorney or someone you trust to look at this Reverse Split proposal with independent eyes and give his or her professional analysis!