Gush and Sundering Titan

[Will]

This came up in a game I was playing last night:

Player A: Activates a Kuldotha Forgemaster Sacrificing 3 Artifacts finding a Sundering Titan and putting it into play.

Player B: Has an Island and a Volcanic Island in play and wants to Gush in response to the Sundering Titan's comes into play ability.

We were somewhat confused because Sundering Titan's ability does not target so you cannot wait until the lands are chosen to Gush like you could with a Wasteland but does this mean that Player B can still respond to Sundering Titan's comes into play ability by Gushing?

[H]

Well, while the ability doesn't target, it does use the Stack.  It can be responded to.  Player B can most certainly Gush in this case, and save the two lands.

The fact that it doesn't target only serves to 'save' Player A from choosing the lands until the ability actually resolves (and not needing targets as the trigger is put on the stack, although I can't think of a time that is really relevant, maybe some corner case with a fetch land).

[Chubby Rain]

Well, while the ability doesn't target, it does use the Stack.  It can be responded to.  Player B can most certainly Gush in this case, and save the two lands.

The fact that it doesn't target only serves to 'save' Player A from choosing the lands until the ability actually resolves (and not needing targets as the trigger is put on the stack, although I can't think of a time that is really relevant, maybe some corner case with a fetch land).

This is correct. As for an instance in which it would be relevant, if Player B were to have three lands in play instead of two, Player A would be guaranteed to hit at least one of the lands. If Sundering Titan's ability targetted, Player B could return the targetted lands to his hand and be left with the third land in play. It is also relevant in that Player B must tap his lands for mana before Player A chooses the lands to be destroyed.