When we were trying to sell our Jayco Eagle recently we had LOTS of scam emails asking for lots of details including the VIN/chassis numbers, rego numbers, our address, making offers etc - and they were people who would refuse to contact us via phone. In return we refused to reply to people via email or SMS.
If someone is genuinely interested, they will call and speak with you. We then asked people to verify who they were. If they are not prepared to provide details then they are not genuine buyers, or sellers.
Be very careful everyone!