As for many cases they do have laws in Thailand but the problem is they don't execute them. Or they don't have anybody to do that properly.
If you get caught by the customs then anything or nothing can happen, depends of your passport, skincolor, dressstyle, creditcards, connections etc etc.
I live in Thailand (partially) for more then 10 years and never heard of those 10 species that are mentioned here. I didn't know that we even cannot export seeds from them.
Maybe they don't open outgoing mail and packages, they sure do open incoming international ones. Never send cash money or valuable things into Thailand because they will never arrive.
If you just want to bring some plants in your luggage and show them to the customs i have no idea what will happen. One day i brought a huge bunch of flowers into Thailand airport and i carried the bunch in my hand openly. The customs had to laugh, let me come over to them and asked for 1 flower for on their desk. Then they let me go.