Every now and then a sign would be so butchered in English that it takes some time of staring at it and looking at your surrounding to really even make out what it is that they are trying to say. That first one is a bad cock up for sure. I think this happens because Thai people are generally too proud to ask a native speaker if what they have written is accurate or not.
a friend of mine was telling me just the other day about a friend who offered his services to the government for free if they ever needed to make a sign. He spoke Thai very well too. They never took him up on it and continue to make nonsensical signs all over town. I think he was just trying to score some govt. connections but you might be right. They probably think it would be lowering themselves to a certain level if they admitted that a native speaker would be better at this than they are. Who knows?