We used something similar to T3R you describe for squirrels in the attic. I think it worked but unfortunately they have to bore a hole in the cornice before they hear the device. As per looking for how rats, etc. get in the house, that is unrealistic. Rats and other rodents have big teeth and can easily bore holes to get in anything wood. I have been on the receiving end of this plenty of times. We paid $5000.00 to have our house cornice repaired after squirrels tore many holes in it. We tried everything to trap them in Hav-a-heart traps, etc. and none of it worked. Unfortunately the only thing that does work is shooting them. Hate to do that but will not have any rodents invading my house. An exterminator probably also kills them one way or the other. My widow neighbors use exterminators and exterminators don't have any good solution. They are calling them over and over again.
We used something similar to T3R you describe for squirrels in the attic. I think it worked but unfortunately they have to bore a hole in the cornice before they hear the device. As per looking for how rats, etc. get in the house, that is unrealistic. Rats and other rodents have big teeth and can easily bore holes to get in anything wood. I have been on the receiving end of this plenty of times. We paid $5000.00 to have our house cornice repaired after squirrels tore many holes in it. We tried everything to trap them in Hav-a-heart traps, etc. and none of it worked. Unfortunately the only thing that does work is shooting them. Hate to do that but will not have any rodents invading my house. An exterminator probably also kills them one way or the other. My widow neighbors use exterminators and exterminators don't have any good solution. They are calling them over and over again.