[sub]it's pretty unnecessary. only people that you've exchanged friend codes with can enter your town, and most people won't pay unsolicited visits. plus, if you don't want to let anyone in your town until they've payed a TBT fee, then you can just leave your gates closed.[/sub]
I'm a unicorn, so I'm too cool to vote. So cool in fact that I didn't vote.
I agree with what the above person said. It's not really necessary. And if someone does start paying you unsolicited visits, I believe you can block them from visiting your town in game without needing to remember which friend card that person belongs to.
I really don't see the logic for the TBT payment, but many people do this (asking to send TBT before the seller gives the items).
When I buy something in TBT, I always ask to receive the things I want, and once I have them in my pockets, I ask the other person to wait until they close their gates, to give me a minute to send them their TBT, and then, I ask them if it worked and if everything is alright. This way, It's less likely I'll be scammed.
Let's say I send my TBT right when I enter a town, and the other person wants to scam me and turns off his connexion right when he receives his TBT... That's bad. Someone did steal me TBTs once, and I couldn't do much about it, that's why I'm taking precautions.
What I do that people seem to appreciate is that I'll give half the payment in TBT before the transaction and the other half after. But you could also do a 2-3 TBT "good faith" prepayment, since 2-3 TBT is easily recovered with just one post, but is also extending the olive branch to the person you're trading with.
When I first started here I waited until I had the item first, but a majority of people on here are trustworthy. If you have doubts, you could always check their wifi feedback rating on their profile.