IMHO LastPass is clear about it. They say: "Savvy end users could potentially access the password if they capture it using advanced techniques during the login

IMHO LastPass is clear about it. They say: "Savvy end users could potentially access the password if they capture it using advanced techniques during the login process". I think this sentence conveys the correct meaning to most people reading it (programmers should understand that the feature is not real security just upon seeing it). I agree that most end-users won't know how to use the inspector, but that's really two clicks on a window of their browser. The blog also goes the complicated way with javascript, but the easiest way (also mentioned) is really really easy: right click on the password, inspect element, click on "properties", scroll down. Using wireshark or modifying /etc/hosts with a custom html file is surely more complicated.