Not just that, but most banks will charge you a withdrawal fee on their end (AUD / CHF / USD/ EUR 5) usually and a percentage charge of up to 3-3.5% of the amount withdrawn.
Only a small handful of banks refund these charges.
Thus withdrawing money from a Thai ATM can be very costly using a foreign card.
You do. I've never come across an international flight where I didn't have interaction with a check-in agent. Even bag drop for internet check-ins have an agent which then checks your passport and visa.
Well, normally I would show them my visa at the check-in counter and not be hassled again afterwards. It does depend on your situation; basically, you should be prepared to show it again though it shouldn't happen.