I'm not sure if assuming everyone is honest because I'm honest is a good practice.
This where people got scammed entrusting funds to escrow without multi-Sig I believe most escrow users don't know about this.
It's definitely NOT a good practice, you will get burned sooner or later.
I think most people get scammed not because of no multi-sig, because their forum account is hacked mid-transaction, and then all hell breaks loose ... Case in point:
https://bitcointalk.org/index.php?topic=5367587.0