Writing Allah’s name on a letter

Is it permissible to write the name of Allah on a letter?  My concern is that we know not where the letter is positioned during the postal operation, such as the floor, which is disrespectful?

If the letter is going through postal delivery then one should not write Allah’s name on it due to it being disrespectful.

Subulas Salaam Vol. 10 Edition 6 Page 16