How do the Romanian guarantees work?

[Ivankovsky]

Hi, I'm trying the "Dracula's Revenge" cheevo, to do this I need to conquer Romania as Yugoslavia basically.
Since Romania is guaranteed by France justifying directly on them isn't going to work, so I opted to justify on Greece instead since Romania is guaranteeing them.
Well I declared on Greece and... nothing, Romania just ignores their guarantee?
Romania doesn't even show in the "Active threats" section when I'm about to declare war, what gives?

 

[Áurum]

Hi, I'm trying the "Dracula's Revenge" cheevo, to do this I need to conquer Romania as Yugoslavia basically.
Since Romania is guaranteed by France justifying directly on them isn't going to work, so I opted to justify on Greece instead since Romania is guaranteeing them.
Well I declared on Greece and... nothing, Romania just ignores their guarantee?
Romania doesn't even show in the "Active threats" section when I'm about to declare war, what gives?

Romania won't attack Yugoslavia to defend Greece because it's also guaranteeing Yugoslavia.

 

[Ivankovsky]

Romania won't attack Yugoslavia to defend Greece because it's also guaranteeing Yugoslavia.

That's strange, since I used this method before to do "Hugeoslavia".
So I assume, since France is also guaranteeing Yugo and Romania they wont get involved if I declare on Romania?

 

[brantodb01]

I think it's a threat thing, if you're Greece and declare on turkey then Romania comes in.
It's just that since you share a border with them they're scared so won't join

 

[Áurum]

That's strange, since I used this method before to do "Hugeoslavia".
So I assume, since France is also guaranteeing Yugo and Romania they wont get involved if I declare on Romania?

It's possible.