We are getting married in a few months and we don't want anybody to know about it! 
(please, no comments about whether or not this is a good idea).
The problem is we need two witnesses to be there in the registry office, to make it official. Is there anyone in a similar position who would like to do a "witness swap" ? We would be witnesses for you, and you would be witnesses for us.
The reason we want to do it this way is so we can be absolutely sure of some reliable witnesses who don't know us - the wedding is stressful enough without this added worry.
Ideas that we've considered and rejected for various valid reasons:
- Asking the registrar to provide witnesses
- Picking someone off the street on the day
- Paying someone, e.g. photographer or make-up artist
- Friends who are sworn to secrecy
- Colleagues
Are you having a secret wedding too? Do you want to swap witnesses duties with us?