The merchant, in this case, is hoping to just use an Android smartphone/tablet with say the Bitcoin Wallet ap installed to accept bitcoin payments. At the end of the day (or week) the merchant would use a Philippines bitcoin exchange to convert the received bitcoin into PHP and have it deposited directly into his bank account.
Initially, bitcoin sales are likely to be only one or two a month so capital outlay has to be kept very low. I can not see him investing even one centavo in anything more complicated.
From the replies that I have received in this thread, it looks like my response to the merchant's "double spend" concerns will be:
There is a very slight risk of a double spend, however you have a greater risk of one of your staff giving free food/coffee to their friend than you have of experiencing a double spend.
A double spend generally requires a customer to spend the exact same amount of bitcoin again within about 10 minutes of the first transaction and that second transaction must be confirmed on the blockchain ledger before the first transaction. None of this is easy to do in the current environment.
I need to keep my response fairly simple. Would this response be reasonable?