The grace period in Thailand primarily allows for the completion of the 90-day reporting requirement but is not a leeway to avoid it altogether. If you are in Thailand for 90 consecutive days, you are still obliged to report, regardless of the grace period. Failure to report could lead to potential fines or issues with immigration.
If you are inside Thailand for 90 consecutive days you are obliged to report. The grace period only applies to the report not the number of days inside Thailand
Anonymous ******************
The grace period is intended for people to complete their 90-day reporting, not as an extra allowance to skip the obligation altogether. It usually won’t be an issue unless you go to an immigration office.