Not true.
They have to proove that the mods themselves caused the failure to whatever is causing your idle to flucuate eradically.

Exhaust will not do that.
Lowering has nothing to do with it either.
The intake wouldn't either -- although they could point at that.

Agian, you dont have to have proof that your mods DIDNT cause the damage, THEY have to show YOU proof that your mods DID cause the damage.