Many of those involved in the critically important period in which omissions of 4th century uncials were adopted wholesale as original readings, were fully aware of the likelihood and danger of accidental and non-original omissions. T.S. Green is an example of an analyist who appears to give more than mere lip-service to the problem of h.t. and other accidental omissions:
"The work of [copying] can never be altogether exempt from the corruptions of mere accident, arising from the wanderings of the eye and the slips of the pen. A place affected by various readings should, therefore, be carefully scanned for the detection of any probable mechanical cause of such mischief, anything likely to betray a copyist into unwitting mistakes. Of the endless shapes which these might take two kinds may be especially mentioned, the interchange of words slightly differing in form, and omissions of words and clauses by oversight." (A Course of Developed Criticism, 1856) intro.