As of this writing (April, 2018), I have yet to hear about a swap deal gone bad or someone getting spammed, but I don’t want you to be the first, so here are a couple of pointers.
Don’t post your email address in a forum message. Remember that the forums are publicly readable, so it’s possible, even likely, that they are being scanned by spammers looking to add to their email lists. Use private messaging (PM) instead. To PM someone, click on their username or icon. A box should appear that includes a message button like this:
Listen to your intuition. If a seller suggests an irreversible transaction like Western Union or mailing gift cards or a buyer wants to send you a check for more than the price and have you send the balance back, it could be a scam, so use caution. Be polite, but don’t let someone talk you into a risky transaction.
The overwhelming majority of forum members are friendly, kind, honest folks, but remember that it only takes an email address to sign up. There’s really no way for Bar and Hannah or anyone else to screen for bad actors. Now that you’re prepared, happy swapping!