What is the likelihood of appeal if a tourist visa entry into Thailand is refused, especially for missionaries or those without sponsorship?

Regarding Multiple Tourist Visa’s obtained outside Thailand.

My recent questions concerned how many Tourists Visa applications are possible and I was advised there is no official limit and Tod Daniels was adamant about this.

However this does not appear to be the case in reality. I am loosely connected with a group of Missionaries who have no church backing so they travel on their own expenses.

It appears that many of these people are being given a hard time at the border crossings and a number have been denied entry recently or given a serious grilling. My neighbour’s are an example of only getting back into Thailand after prolonged interrogation about their source of funding.

It seems that regardless of the Tourist Visa rules it is finally down to the immigration officer at the border who has the final say.

Recently the situation has become much more difficult and so I too am concerned for the entry clearance of my fiancee from the Philippines who is dependent upon me as a Non O retiree as she also travels on a Tourist Visa.

So is there a possibility of appeal should an entry be refused.