It's 90 days, not 3 months. There is a difference.
No entry is guaranteed. You could very likely be denied entry either time, or given a free pass both times. No way to know until you try.
Remember, Canada, Mexico and "adjacent territories" count toward your 90 days.
Read FAQ 252 for more.

If you are denied entry, you will no longer be able to use the VWP ever again, even to transit, would be sent back to your port of embarkation (the place you just came from, which may or may not be your…

Actually the last bit has been removed from the law, and is no longer enforced. therefore people that do this are not actually breaching the law.

However they have now made it more difficult to do this, as those people are now forced to use airports, as those 41+ countries are limited to only two overland entries in each calendar year, but people trying to enter Thailand by air, and have more than 3 consequetive or back to back visa exempt entries, stand a big chance to be denied entry.

No, you are not required proof of onward travel. Having the visa grants you entry into Thailand. Therefore, Emirates is off the hook for their responsibility. They will ask for 'proof of onward travel' OR 'a valid visa', NOT both. You are good to go. No worries. Again, the visa ensures that you will be granted entry into Thailand, and Emirates does not have to worry about repatriating you in the event you are denied entry.

4. Some time in the future you need to enter Serbia again through a 3rd state/Serbian border with the same passport. At this point you have a Serbian entry stamp, but no exit stamp, and you can be denied entry.

Hmm. I went through Serbia last year, and they never stamped my passport when I left to Bulgaria. The entry stamp is fuzzy too. Will I have a problem entering on Beograd airport this summer?

Any evidence of having been to Israel - either in your passport or elsewhere - denies you entry to Syria. This may also be indirect evidence such as a missing Jordanian entry/exit stamp - and they check your passport thoroughly to see if you have a "proper" sequence of entry and exit stamps for the region.

The general rule to follow: If you absolutely must return to Syria after visiting Israel, don't go to Israel on your current trip.

No, it does happen from time to time, though of course it's not the majority of visitors. The security officers do put people in the prison even if they don't have anything offensive on the person, but are just awaiting additionnal information on him/her. Since there is no hotel for people awaiting entry, they put them in the prison, where you can sleep in a cell. It's a question of practicality. Then some of the "inmates" are denied entry and others are allowed entry.

I paid the fee to transfer the visa into the new passport. They may let you into India without doing this but I think it better safe than sorry.

They did not limit the number of entries when we transfered the visa.

If you have a multiple entry visa, you will still have one when you switch it.

The process is simple and not a fortune. A mere pittance compared to being denied a boarding onto the airplane or entry into the country due to this technicality.

In July I will be driving you canada with summer friends. I do have theft, party to a crime and reviving stolen property on my record. I was convicted about 6 years ago, no jail sentence or anything, and only a misdemeanor. But im worried I could be denied entry. can I check if I'll be denied before I drive all the way there??

Can only confirm what others have said. There are very many countries with a regulation of this kind. Madagascar is another that can be added to the list.

You'll have to go get yourself a new passport, or you're very likely to be denied boarding. Airlines that fly someone to a country where they are denied entry due to non-compliance with visa regulations are subject to a heavy fine and have to transport the person back to the starting point at their own expense.

Bill Gates - of M/S fame was recently denied a visa to Nigeria until he could prove that he wouldn't be a strain on their social services !! Or so the report has it.

Gates Denied Visa

David