Transparency is relative to the size and scope of your reunion. When my family held large reunions in the past, reunion finance info was basically non-existent. Of course, this was back in the mid-late 1980's, before the laptop and the internet(LOL). Back then, family members just sort of showed up with money in hand.(Of course, some family members are still trying to pull the pay as you show up stunt.) Finance info was a receipt that said that you paid. It was a sad state of affairs!

Today, we are a much smaller reunion group and our reunion committee is very transparent. We are more enlightened about finances and yes, we have access to a computer. We have a reunion planning committee, which includes a finance team.
We usually go over finances during monthly reunion planning committee meetings. Family members are encouraged to attend the meetings, however, most of my family opts to skip the meetings(LOL). Spreadsheets of all our reunion's finance activities are available to family members via a members only area on yahoo groups. This includes reunion expenses, fundraising income, banking withdrawals/depoists, and payments made for reunion activities. In addition to spreadsheets, we also keep a book/folder with paper info including receipts, contracts, bank account info, etc.
A reunion closing session is held during the reunion to discuss among other things, finances and the next reunion.