Given a travel related situation, and given a specific question about the situation, summarize the question into a title

Input: Consider Input: I am applying to the French embassy for a one-month Schengen visa. For proof of sufficient means, I have my bank statement (with slightly over $7000) and monthly pay slips (of about $1500). The document requirements say that I need to submit 3 years of IT returns, but I've only been working for 2 years and haven't filed IT returns even for those years. Can this be a cause for possible rejection of my application?

Output: Are the tax return document mandatory for a Schengen visa?

Input: Consider Input: Is it possible to get Mongolian currency (the Mongolian Tugrik) in Sydney, Australia?

I tried looking at Travelex, Australia post, and Westpac, and none of them seem to offer Mongolian currency.

A blog called No More Maps says that it's not possible to get Mongolian currency outside of Mongolia:

Where to buy tughriks?

In Mongolia of course. There is no way to buy them abroad. Neither
there is a way to exchange them back while staying abroad. Here is the
current rate for 1000 MNT.

Do I have to wait until I get to Mongolia to get Mongolian currency?

Output: Is it possible to get Mongolian currency in Sydney?

Input: Consider Input: I am a US citizen who will have worked for 89 days in a Schengen country while on a 90-day tourist visa.

What exactly is my best strategy at US border control? Should I admit to working while travelling, or lie and say I was on vacation?

I fully intend to declare the income earned on my taxes for this year, but I simply want to minimize trouble at the border.
Output: Returning to US after illegally working in the Schengen area