In Genesis 31:32 we have Yaakov's response to Lavan's charge that someone in Yaakov's party had stolen something from Lavan.
עִם אֲשֶׁר תִּמְצָא אֶת אֱלֹהֶיךָ לֹא יִחְיֶה נֶגֶד אַחֵינוּ הַכֶּר לְךָ מָה עִמָּדִי וְקַח לָךְ וְלֹא יָדַע יַעֲקֹב כִּי רָחֵל גְּנָבָתַם
With whomsoever thou findest thy gods he shall not live; before our brethren discern thou what is thine with me, and take it to thee. --For Jacob knew not that Rachel had stolen them.-- (Mechon Mamre)
In Genesis 44:9 we have the brothers' response to the charge that someone in their party had stolen something from Yosef.
אֲשֶׁר יִמָּצֵא אִתּוֹ מֵעֲבָדֶיךָ וָמֵת וְגַם אֲנַחְנוּ נִהְיֶה לַאדֹנִי לַעֲבָדִים
With whomsoever of thy servants it be found, let him die, and we also will be my lord's bondmen. (Mechon Mamre)
Rashi cites the Midrashic idea that the declaration of Yaakov ultimately caused the death of Rachel.
ומאותה קללה מתה רחל בדרך
And from that curse Rachel died on the road.
However, there is no indication that Binyamin ever suffered any ill on account of the similar declaration made about him.
What is the difference between Yaakov's declaration about Rachel and the brothers' declaration about Binyamin, such that Yaakov's declaration caused the death of Rachel while the brothers' declaration did not cause any harm to befall Binyamin?
Is there any indication that perhaps Yaakov's declaration was specifically meant as a curse, not a directive to Lavan, while the brothers' declaration was specifically meant as a directive to Yosef, not a curse, and thus Yaakov's curse was fulfilled but Yosef simply opted not to follow the brothers' directive? Perhaps this is implied from the fact that they also sentenced themselves to slavery? And is that something that would mitigate the possible negative effect of the declaration?
And perhaps related: were the brothers aware that Yaakov's curse had caused the death of Rachel, and should they therefore have been more careful with their words? Especially considering that someone had snuck things into their bags on their previous visit and could easily have done the same this time?