No, unless they allow wind, water, and insects to enter your log home or cabin. Checks are a natural way for the logs to breathe. If you have filled some, be sure to inspect them often for breaks in the caulk. If water gets behind the caulk, the wood can’t dry out fast enough and will cause log rot!
No, do not paint your logs. Paint will not allow the wood to breathe properly and could lead to premature damage. You are able to paint Cedar siding with having minimal to no water problems. It is not recommended or ideal to paint the cedar siding but it is possible if the procedure is done correctly.
Never power wash your log home! The pressure can damage logs and drive water deep into the wood where it may never dry. With cedar sided homes you can rinse the boards but not too heavily because water can and will penetrate all the way through the boards trapping moisture between the house and the siding.