On these lines for people here in the states that do not know this.

Visa does not count emails or UPS tracking as a confirmation that the person received the package UNLESS it is signed for.

I do not know about everyone else here but most of the time my UPS driver just drops and runs.

We lost one charge back dispute due to this "the only one we ever lost".

We had emails from the customer stating they received the item.
We had the UPS tracking showing it was delivered.

The person disputed with their bank that they did not receive it.

Visa stated:
Emails can be changed.
UPS tracking does not mean the person actually received the item.

So it cost us $25 for the charge back + we gave them a free item. "We did get the insurance for it".

We now send everything signature required.
Just a heads up on this.
We have added also in our FAQ that if a dispute is filed and we win the dispute, we have rights to charge their card any fee incurred by them filing the dispute. We have done this with no issues as it is written on our page (part of our policy).