Stupid disclaimer

Today I received a business proposal with the following disclaimer:

“E-mails are susceptible to corruption, interception and unauthorized amendment, reason for which the sender does not responsible for possible alterations of the original text and their consequences.”

Well, if that is the case, how should I:

a) Take this seriously?
b) Make sure the proposed price will be final?

So, what do I need? A signed paper hand delivered?