Some places (and some families) developed a habit of having more than the required two witnesses. It seems more common where a family thought of themselves as "professional".
The first in my tree is in 1870. Several events have four witnesses, three have five and the last "oversubscribed" one, in 1948, has six signatures.
Of course these are well beaten by Quaker marriages, where it was normal for all who attended to put their name to the record, even in the period when such gatherings were illegal, in effect confessing to a crime. One I have, from 1689, bears the names of 58 witnesses.
