Every lease which i have had over the 14 years here I have had a clause in it stating if I am leaving Thailand I only need to give 30 day notice. They all been 12 month leases, 5 different agents, none of them had an issue including in lease, only had to use the once.
that day there were more people with e visa's than VOA, it is the same as arriving in Thailand, luck of the draw if immigration is busy or quiet, only bonus with E Visa is you don't lose a whole page in your passport