What does it mean if someone receives a stamp at BKK airport denying entry into Thailand?

A friend was denied entry into Thailand at BKK airport and received a stamp indicating insufficient funds. The community clarified that this stamp does not necessarily mean he is blacklisted, but rather that entry was denied under Article 12, Section 2 due to a lack of financial proof. It was suggested that he should consider applying for a visa in advance for better chances of re-entry, as the decision ultimately lies with the immigration officer at the time of entry. Other recommendations included trying a different entry point.