Can Spelleater Curse be used to stop a spell that cannot be unbound?

[yukishiro1]

The text says:

Quote

Choose this reward immediately after a WIZARD
has cast a spell anywhere on the battlefield,
before any attempts to unbind that spell are
made. That spell is not successfully cast.

The effect of this is essentially to unbind the spell, but it doesn't say actually say the spell is unbound - and in fact it specifically says it happens before any unbinding attempt, and that the result is not that the spell is unbound, but that it simply "isn't successfully cast." So does this mean you can use it to stop a spell that cannot be unbound, e.g. Teclis when he only casts 1 spell or a spell-in-a-bottle endless spell? My read is yes, it will stop anything, but I can also see the other argument. 

[Fert]

If you compare the rules text as written then yes.  In addition, you are apply this special rule in section 19.1 immediately after "the spell is successfully cast" and never get to section 19.1.2 which is where unbinds occur.

However, if you are attending an event then contact the TO prior for his interpretation and provide these rules as reference.

[Liquidsteel]

Yeah for example Teclis says the spells can't be unbound, but this says the spell is simply not cast.

[BorderPhantasm]

I don't believe it would stop a Spell in a Bottle spell as it is not a Wizard casting it.

[yukishiro1]

Oh, that's an interesting point. Weirdly enough, Spell in a Bottle doesn't even say it's cast "as if you were a wizard," it just says you can cast the spell, period. So I guess you're right, you can't stop it (unless they took arcane tome and made that dude a wizard, then you can...lol).