mail attachments are downloaded automatically while in standby

Hello,

Is this normal?

When the phone is in standby it switched to 3G, i know that this is by design,

However, when in standby and e-mail from an exchange server is received with an attachment the attachment is fully downloaded automatically.

When the phone is not in standby users have the option to download the attachment.

I tested this with severel iphone in our company and it seems that this is also by design???????

This is not a good thing because here is no such thing as unlimited data. Very strange strategy if this is by design.

thanks,

Ron