Master cards attached to a stolen minion

Dear all,

I would need a confirmation please. If I steal a minion who has got attached master cards. As far as I know, if those masters card text does not say anything special, the player who played them is still controling them.

Exemple 1 :
- Perfectionnist : Can I choose wether to activate that master effect or only that master's controler can?
- Corporal Revervoir : Can I choose wether to activate that master effect or only that master's controler can ?

I think I cannot but I would appreciate confirmation and reasons.

Card texts :
Perfectionist
Put this card on a vampire you control. Once each turn, this vampire can gain 1 blood after performing a successful action during which no reaction cards are played. A vampire can have only one archetype.

Corporal Reservoir
Put this card on any Black Hand vampire. This vampire may lock this card to prevent 1 point of damage in combat or to gain a blood. This card doesn't unlock as normal. This vampire may burn a blood to unlock this card during his or her unlock phase.

Thanks in advance,
Regards,
Rémi.

I would have argued that you can, because the vampire chooses: "this vampire can gain 1 blood", "This vampire may lock this card".

But it's a good question.

I would argue the same way as lip, the wording implies that the vampire the card is attached to chooses, and by extension it's controller, not the controller of the card.

www.vekn.net/forum/rules-questions/78398-the-rack-vs-changing-control#98819

In this topic the same question was asked regarding The Rack and a stolen vampire. Since The Rack and the cards in question here all have the wording "this vampire can...", it should work.