QUOTE(AusCal @ Apr 17 2008, 06:43 PM)

It would depend on whether the person opening the envelope noticed two separate applications, and issued two "receipts". Personally, I think even if the risk is minimal it is simply not worth taking - the potential delays/hassles it could cause is simply not worth it to save a couple of dollars - JMHO
I totally agree with AusCal. However what you could do is have two totally separate envelopes for you and your sister like you would send them separate. Then you could put both of these envelopes inside another envelope that you mail. This way the person who opens the packet is forced to notice two applications. Make sure both applications have their own cover letter, etc. Good luck.