3.2 Script Loading

Video player scripts should only start loading when requested by the user

Easy to implement
8
High impact score

Introduction:

Even the embed of a third party video causes data transfer and so this should only happen when the user requests it. 

A fake video thumbnail is a nice way to achieve this, as demonstrated by The Climate Group.  

You can autoplay once the embed is loaded to avoid the user having to click twice. In this circumstance, the autoplay is acceptable.