The Rule Compendium, page 76 (invisibility) introduces the concept that it is possible to spot an invisible character within 30 feet (with a spot check that would be minimum 20+20= DC40).

Does this mean that, without any spell to see invisibility, a character invisible at 31 feet is impossible to be spotted?

example scenario: A rogue that is invisible (with superior invisibility) and incorporeal (no sound, no traces), does a full round ranged sneak attack to a target that is 40 feet away. If the target has no way to see invisibility, does this mean that the target fails automatically any spot check?

PS. This would mean that the rogue does not need to use the hide skill.

Example scenario if a target had a spell to see invisibility:

A rogue that is invisible (with superior invisibility) and incorporeal (no sound, no traces), does a full round ranged sneak attack to a target that is 130 feet away. The target has a true seeing spell on but the range of the spell is 120 feet, does this mean that the target fails automatically any spot check?