Does silence mean consent?

無言是否代表默許同意 ?  
Does silence mean consent? 

Here is an explanation from: http://www.rakehellrow.com/bali/sexualassault/whatyeslookslike.html

Consent is a mutual verbal, physical, and emotional agreement that happens without manipulation, threats, or head games.

I agree with the "What does YES look like" interpretation in a sexual-assault context. 

But how abt the silent majority in an open election with low voters turn-out? 

Are they consenting to anything by refusing to cast a vote and express an opinion??