Fine, I'll be more clear.
The idea that no proof is possible is trivially easy to disprove. If an all-powerful being exists, that being must have the power to prove it's own existence. No such proof exists, and therefore it becomes necessary to invent excuses for the all-powerful being.
When a religious person says no proof is possible, what they're really saying is that they have a pet list of these excuses.
When it becomes necessary to invent excuses and there's that pet list, how does that make it trivial to disprove that no proof is possible? I think it's more trivial to prove that proof is impossible. For example (here's my pet list):
beyond time and space (so, undetectable)
has a master plan that accommodates anything anyone can ever think or do, ever
can make a rock so heavy, even he/she/it cannot lift it, and then lift it (contradict itself)
unlimited everything, invincible, all weapons, unlimited ammo, all spells, unlimited mana, no clipping, super jump, unlimited 1-ups, rainbow yoshi, etc. (that's probably just my god)
As I typed earlier, too much of it (maybe all of it?) is cleverly built to require faith.