A pertinent question is *why* you overstayed so many, many, many times?
I got a 20K Baht overstay in 2015 which was 100% my own fault. What happened was I confused the "report your address by" date with the visa expiry date. Since then I have learned from that mistake.
I also got one in 2018 which was *not* my fault; the agency I was an employee of as a teacher cancelled several employees' work permits without telling us, thus invalidating our reasons for extension and causing us to be on overstay without our knowledge.
How did you not learn from the first, or at least the second one? You say you've had "a few" 20K overstays, which implies it was more than two. To get a one year ban means you then went on to overstay by more than *90* days.
If denied entry, and you're lucky, they will give you the option of flying out to a country of your choice.
If you're unlucky, they'll insist you go back to where you just came from. If you're *very* unlucky, you'll be forced to return to your *passport origin* country.
Obviously, they very much *can* see your entire history with a scan and a click of a button, across all passports past and present.
However, they won't *necessarily* do that check, like if they've had a long day, are about to come off shift, theres a very long line etc. So getting a new passport isn't *completely* without advantages.
That said, the days of being able to get a 100% pristine new slate with a new passport are very much over, and if they *do* make that check..... well, be prepared for a long chat in the back room, and potentially a denial of entry.
Probably depends on what the sentence, and what kind of visa you're going for.
When I got the teaching job I have now, I was required by my school to get an International Child Protection Certificate from my home country (UK), which as the name suggests entails a thorough background check for any convictions or allegations made against you ever, when it comes to children.
However, the IPCC requirement was particular to my school, I think, and I believe for most schools the legally required process for getting the visa is that the authorities contact your home authorities and ask for a basic check. Don't think there will be any Stat of Limitations on the serious stuff for that visa though.
Probably some overzealous officer trying to impress someone and failing.
A few years back, here in Chiang Mai, a load of officers turned up to Zoes at like 11pm and took into custody a load of foreigners who didn't have their passports on them (because of course; who *doesn't* have their passport with them while they're out partying?).
After all that malarkey, questioning, and even blood testing, looking for visa overstayers and people who'd taken or smoked anything illegal, they found a grand total of.... ZERO such cases.
Zilch. Nowt. Nada. To use the Thai word: Soon.
From what I hear, a few very sheepish individual officers got summoned for "clarification on what happened" (Thai cultural translation: Getting a massive bollocking), and there were a few "transfers to inactive posts".
Always worth checking here when planning stuff that involves dealing with any government department.
Also worth remembering that if you go for your extension 1-2 weeks before your expiry date, you don't lose any time; the extension is added to your *existing* date, not the date you applied for the extension.
There's no *official* limit to air entries. On paper, you can do it forever.
However, the more visa-exempt entry stamps you have in your passport, back-to-back, the greater the likelihood that you'll be pulled aside at immigration and interrogated as to what you're doing here, and potentially denied entry, or worst-cast-scenario deported back to your country of origin.
When that point comes will vary from officer to officer.
Some people get questioned after their second or third entry stamp.
Others get away with it for well over a year.
"How long can I stay here on short-term stays" is one of those "How long is a piece of string" questions.
You can do it until you can't; until they tell you "No More".