If the purpose of an EMail column is to be able to supply it to a Bulk Mail process, then "yes" I think it reasonable that the address should satisfy that requirement (AND be validated, within reason - i.e. "Looks OK" rather than "Is deliverable").
We built a data import from a very well known 3rd party Accounts / ERP system that a client is using. Nothing of any value seems to be validated:
Country Code - any old rubbish, typically the last line of the address winds up in this. We reject the whole record on import on the grounds that WE do actually REQUIRE a country code (for geographic analysis)
Email - client has multiple email addresses in the column (";" separated). I suppose that's OK, and maybe a direct feed to a Bulk EMail program would treat those as a TO: or CC: block ...
... but when we question the Client they say that it would be a disaster to email all those addresses because they are "anyone we have ever known", so could be sending Trade Price (or somesuch) details to someone who would be horrified to know how cheaply products were being bought ... so in our APP we split the Email addresses, put then in a "Contacts" sub table, and the Client has to then mark them up as to what-type-of-contact-that-actually-is. Would be much better if they did that in the ERP APP ... by the time it gets to us there is not much appetite to clean them up, so result is that Sales say that lots of Customers complain that they don't get emails about the special offers, and consequently the Company is losing business
VAT (our Sales Tax) numbers. We have an arrangement for reciprocal charging, and claiming-back, across the EU countries. All EU countries have VAT numbers that conform to a checksum validation. Yup, you guessed it, the ERP doesn't bother to perform any checks at all.
Max address line length? Anything you like ... doesn't matter that it won't even begin to fit on an envelop or an Address Label. So we have to reject those too, and Accounts have to tidy up the address each time they just blindly Cut & Paste them into the ERP.
Soap Box? Mine definitely isn't tall enough, or big enough for my requirements