True. However, it's not arbitrary if the ISP says I'm not going to provide
store and forward services for email over 100k (although I usually use 1Meg
as the cutoff). If you want to do something different in your office or
pay for the resources to host some sort of multi-terrabyte mailserver and
the bandwidth to handle all the retries, latent failures, etc., go for it.
Personally, I choose not to accept the headaches for users that don't know
how to use computers.
While "Parcel Post" is arguably valid, there are better methods of achieving
the desired result that are much more net-friendly, user-polite, and efficient.
To further your analogy, parcel post generally accepts packages up to 50#,
nothing more. This is approximately 800 times the weight of a standard letter.
(50 pounds == 800 ounces, and first class letter pricing is based on one ounce
A standard email message is usually less than 32k. 800 times 32k is 25600k,
or about 25 Megabytes. Therefore, using your analogy, it is reasonable to
limit parcel post to 25 Megs. This is giving you substantial bennefit of
the doubt here, as the largest non-attachment email I could find in my inbox
was about 10k (making the parallel limit more like 8 Megs).
Denying other users resources on a store-and-forward system you don't own
by sending large attachments is, in and of itself, arguably a denial of