Is non-payment cheaper than donations?
Taxes are in hindsight so you've already made whatever donations you did by the time you paid taxes.
Donations either lower your tax bill or have no effect on it. So, by not filling taxes (_and getting caught_) you're just increasing your tax bill.
...but then tax you on the interest they paid you if you claim it.
Do you have a source handy? My Google-fu is failing and only bringing up interest on unpaid taxes.