NO NO NO NO NO NO.....Except in Dire emergancies like need to apply First aid / M2M or CPR

You never leave your boat. If someone cannot right their boat, if you get off to help them chances are that your boat will capsize. The only time I would consider it was if you had taken all sails down and could moor to a bouy (thus it will not move).

One other (last ditch method) would be the following (I.e no bouy and you really really need to go help some one):

1, Take sail(s) down - replace the halyard with the mainsheet and Spi sheets if you have them and tie to the base of the mast ball , take mainsheet blocks off the back beam and boom and tie it to the downhaul eye at the luff of the sail, tie / shackle the boom to the outhaul eye on the foot of the sail - Basically try and tie as much dead mass to the bottom of the mainsail.

2, Throw all this off the front of your boat, you have now made a considerable sea anchor and so might be able to help control/limit the amout your boat might drift.

However, if you are sailing single handed, out of site of land, I would suggest taking the following:

1, A set of flares (The first one may not been seen)
2, A mobile Phone in a Aquapac type bag
3, A GPS (and learn how to use it)
4, A small plastic mirror.

A combination of above should allow you to get some help. And tell people wher you are planning to sail