Methyl, I really don't know where you're coming from, I've been to Thailand 3 times with my OH and 2 kids and have never been robbed or indeed felt we came close, small business holders will try to rip you off, but you get that here. Exercise the caution as you would anywhere else and you'll be safe. Agree with 237, cash is king, I'd probably only use a card in a bank.
Take no notice of Methyl, go and have a fabulous time, it's called the Land of Smiles for a reason. Millions of tourists travel there every year without problems, the first time we went my kids were 5 & 7 years old and they loved it, infact the last time we went we gave them a choice, Florida?, no they said Thailand.