Yes, 'bad behaviour' by family members (you and your mother) can be used against a visa applicant.
You didn't tell us her immigration status in the UK ... a VERY IMPORTANT fact. Plus, it would help if we knew whether or not she has a husband, kids and a job in the UK ... 'cementing' her ties to the UK and lessening the chances that she will follow you and your mother's 'lead' in breaking your visas.
Lastly, London is known for being a very tough Consular Post ... it would help if she paid an attorney (there are many in London that have a US license) for assistance.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- firstname.lastname@example.org -- www.capriotti.com -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.
There's no possible way to know. There are many, many factors that could be at play here and a sentence or two explanation is almost certainly not enough to figure this out. If you want personalized advice, you should contact a lawyer who can review the file and talk with the parties to see what is going on.
This is not legal advice and no attorney-client relationship has been formed, now or in the future. This is just a casual opinion expressed about a hypothetical situation.
I am sorry to hear that. I think what you stated in your P.S. was one of the main reasons for her visa denials, i.e., immigrant intent.
Law Office of Brian H. Lee, San Jose, California, 408.246.6710 This is general information, not legal advice. This does not establish any attorney client relationship.
She needs to show an unabandoned foreign residence to which she intends to return. Since she is living outside of her country, has no family ties to where she lives, perhaps has minimal property ties, she has every incentive to do what you did. The officer did not feel at all confident she intended to return to any particular place when the graduation was over.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.