As-salamu alaykum Regarding one of the previous asks about lying to turn someone down: are there not circumstances where it is forgivable? I am unsure what kind of invitation the previous asker was wondering about, but in my own life there are circumstances where strange men may ask me personal information and whether I'm available and I feel I have to lie - even about my name - for my own safety. Of course I try to limit my encounters, but I can't avoid going to work or class or using the metro
Alaikumassalam wa rahmatullah,
Honesty is one of the most important values in Islam. If you fear for your safety, then in such a situation lying may be justified. According to a saying of the Prophet 
, lying is justified in three cases: 1. in times of active war 2. in order to mend relationships between people and 3. white lies between a husband and wife when telling the truth may be damaging to the relationship (thus a man is allowed to tell his wife she is beautiful even if at that moment he does not find her beautiful).
According to a quotation provided by Imam al-Ghazali, lying is also justified in order to save someone’s life (the example he gives is this: if you meet someone who wants to kill an innocent person, it is obligatory to lie to them for example by telling them the person is not where they are so that the killer will not find them). Since in your case it is a matter of safety and possibly life and death, it seems to me that lying may be justified.
References
- Fatwa from the Qatari Fatwa Authority (Arabic PDF)
- Fatwa from IslamOnline (Arabic PDF)