I guess if you buy used off the EE you're hooped for warranty work if something goes tits up on an eotech since there won't be a receipt.
Not sure, they took my XPS2-2 back for the refund without a receipt.
OP, If they won't warranty it or it's going to cost you money just buy an Aimpoint, I have a T1 and a PRO and they're both fantastic with insane battery life and always hold zero. You can usually find a PRO on the EE for under $500.
Good luck