Word collection ('most useless' category)

My trusty friend Chambers just offered me the following:

'Haplography: the inadvertent writing once of what should have been written twice.'

Eh?

OK, I suppose I could have written 'ofered' and writen'.  Or how about 'betrot'?  But has this haplography word ever actualy ben used?  Especialy now we have spelcheck?

Language is very very strange, init?