I will say that a good scammer will circumvent a lot of the “earning trust” stage.
Through social engineering or just sheer luck, they will catch you at a time when your guard is down and they will manipulate a sense of urgency.
“Hi mom, my phone fell in the toilet and I really need it for work tomorrow. I’m using a friends phone right now, all my bank access was on that phone. I’m so stressed. Can you send me $800 via (dodgy website) so I can buy a new phone and get to work”.
Instantly hits on an emotional pressure point. Adds a huge sense of urgency, with good reasons for an untrusted number and a dodgy payment method, and makes it seem difficult to corroborate with the mom’s kid.
“Hello, this is your real estate agent. Unfortunately there has been a complication with the purchase of your new house. Due to extra fees, $10,000 needs to be transferred to X by midnight, otherwise the banks will reject the purchase/mortgage/whatever. Sorry for the out-of-hours contacts, I’m currently in (city) on other business and not in the office”
Another hugely stressful scenario. Massive sense of urgency with a disastrous deadline.
People don’t buy houses every day, and may not be fully aware of the process. They might take this as an unexpected but legit part of the process.
Obviously, this requires significant social engineering to set the scam up in the first place (knowing someone is buying a house and roughly when). But the payout can be significant.
The biggest piece of advice I can give is:
If someone is applying a sense of urgency on any decision: STOP.
Take a breather, think about the scenario. And then contact “the person/company” via another way through means you research yourself.
If it’s on the phone, ask for a case number, Google the company and phone them directly. By text or email, same thing. Find their phone number via Google.
If it is legitimate, an extra 30m isn’t going to harm anything. Especially if you say “sorry about that, I wasn’t sure if it was a scam or not”.