Automatically Failed Saves

[the Federation]

So I'm creating a new character based on the BJJ Build from The Grappler's Manual (http://community.wizards.com/comment/51292946). I thought I read somewhere that when a creature's speed is reduced to 0, it automatically fails Dex saves. Is this true, or am I just crazy(-er)?

And once we're on the topic, what are other ways to make a creature automatically fail a saving throw/opposed check of any kind?

Answers don't have to be confined to the PHB, as long as they're official (no house-rules) such as Mike Mearls's official tweets, and sources would be nice.

[jaydubs]

The restrained condition sets a creatures speed at 0, but also gives it disadvantage on dexterity saving throws. If having 0 speed caused dex saves to automatically fail, the disadvantage would be pointless. I infer from that that dex saves don't automatically fail at speed 0.

Grapples are also an opposed ability check rather than a saving throw if I recall correctly. But I'm guessing you're actually referencing something specific above and beyond grappling from the grappler's manual (haven't read it).

Some ways to cause auto-failure:

Blinded - Ability checks that require sight.
Deafened - Ability checks that require hearing.
Paralyzed, Petrified, Stunned, Unconscious - Strength and dexterity saving throws.