@Ju *****
Thailand records your entry and exit against your passport. If you're currently in Thailand, Immigration will have an entry record without a corresponding departure. I don't know whether embassy staff automatically check that database on every DTV application, but I certainly wouldn't assume they can't verify it.
They can also request additional evidence or require you to attend an in-person interview, which is another way of verifying physical presence.
Best to just play by the rules.