Something is going on, I know someone who has just been refused travel from UK (airline supposed to have contacted Bangkok immigration to confirm) having travelled on exempt 2 times in the last year. Below from London embassy site. The first line says only 2 entries per year with no explanation but then further down it sepecifies by land and sea.
Tourist Visa Exemption Scheme
UK ordinary passport holders can travel to Thailand without visa for no longer than 30 days (maximum 2 times/year).
All UK travel documents (Refugee/Emergency) must apply for the visa before traveling to Thailand.
- Foreigners entering Thailand by any means under the Visa Exemption scheme are required at the port of entry to have proof of planned travel (confirmed air, train, bus, or boat tickets) to leave Thailand within 30 days of the arrival date. Otherwise, a visa must be obtained before entering Thailand.
- For traveling to Thailand by land and sea, UK ordinary passport holders are eligible for Visa Exemption Scheme with a maximum of twice in a calendar year.
going on, I know someone who has been refused travel from UK having travelled on exempt 2 times in the last year.