If you did not attach 10th class certificate (Matric) while applying for passport, you used to get passport with words printed on second page :" Emigration Clearence Required blah blah blah...." Then you were supposed to go to passport office again (people also used touts with cost about 1000 Rs) to get this paragraph striked, and Passport Officer's signature and stamp saying ECNR on same page.
If you attached educational certificate, then it used to get striked auto on issuance.
If you are going on a work visa to Gulf or few other countries, and has ECR status, border control will notice and will not let you go out of country without ECNR. Immigration officer will make you go back and get the ECNR from passport officer of your area/district. This essentially means you will miss the flight.
Regarding the try to circumvent it, by going to Nepal and flying from there, I believe this is possible, as many people go to Iraq/Syria etc for work (because agents promised them moon and back salaries because of war zone) via Dubai/Nepal. India does not allow people to go to Iraq/Syria for work, so people just say, have visa, for Dubai/Gulf.
Like any other country, you check-in at airline counter, get boarding passess, and need to go through immigration if international flight. There Immigration Officer will check boarding pass, will ask the reason of travel, and might want to see the documents you will use to enter your destination. If the destination is on list, and you are going for work, he will check the ECR/ECNR/POE, and you essentially will not be allowed to cross the border (need to go back to sort it).
Relevant Quote from Buraeu of Immigration, India
As per the Emigration Act, 1983, Emigration Check Required (ECR) categories of Indian passport holders, require to obtain "Emigration Clearance" from the office of Protector of Emigrants (POE), Ministry of Overseas Indian Affairs for going to following 18 countries.
United Arab Emirates (UAE), The Kingdom of Saudi Arabia (KSA), Qatar, Oman, Kuwait, Bahrain, Malaysia, Libya, Jordan, Yemen, Sudan, Afghanistan, Indonesia, Syria, Lebanon, Thailand, Iraq (emigration banned).
Some more info from ImmiHelp
this website does not allow me to select text on mobile?
Source: I co-ordinate between 70+ mixed nationalities employees and Official HR Department for these all visa/travel related processess in a Gulf Country.