@Graham *****
just opposed to your opinion...
And my opinion is also shared by Thai embassy.
"Foreigners entering Thailand under the Tourist Visa Exemption category must show the documents below at the port of entry:
Proof of adequate finances for the duration of stay in Thailand i.e. traveller’s cheque or cash equivalent to 20,000 Baht per person and 40,000 Baht per family.
Proof of onward travel (confirmed air, train, bus or boat tickets) to leave Thailand within 30 days of the arrival date (**otherwise a tourist visa must be obtained)."
Obviously they forgot to change 30 into 60 at this place, but in this case that is irrelevant