This makes the alias harder to remember though, which subtracts from the main purpose of aliases.
What do u prefer:
1. Send to 2587623823894059467
2. Send to John726
?
Would prefer sending to 2587623823894059467[check digits] when I need to enter the entire address and unable to use aliases, and sending to John, or John276, or any other alias of my choice when I can. If I use alias, I do so accepting the consequences of mistyping. I think most regular folks would also feel like this.
EDIT: On further thought, some regular folks would feel like this. Some would just be careless.
There are still 192 reserved bits in addresses right? Maybe can spare some as check bits?
We can't.
But if it's impossible at the protocol level, then maybe we can look at safeguards at the client level. Maybe clients can (at least have the option of) enforcing check digits for entering naked addresses.