The real question which I suspect no one can answer is would the people who pinch the images otherwise pay for them? if not then you are not actually losing any income! I suspect many will take them for their facebook image then replace it next week on whebever. If they couldnt pinch it they probably wouldnt be fussed as they dont put much value on a photo anyway.
back to econmics lessons, would you sell more if you priced lower and therefore make more money? Supply and demand really is underneath all this....
two things here:
1. economics lessons: below a certain price it doesn't make a difference for event photography - it does not increase demand linearly: i.e. half the price = double the sales. This is not true.
Conversely - if we consider photos to be a "luxury" product as defined in economic terms - with it's inverse response curve - an increase in price does not increase demand.
Basically, if they want the picture - they will buy it. If they really want it they will pay silly money (ref: marathonphotos). If they want the image, just to show a friend (i.e. pointing something out in a shop window to a friend) they don't think anything of copy and paste (i.e. shoplifting) - because it is so easy.
The trouble is that with photos - showing them to others is the intrinsic value of the image!
So I think it comes down to how valuable that moment and memory was to that person, and also to a certain extent how much that person values themselves. Which as self-employed people - we know how easy it is to undervalue oneself all too easily.
So - don't drop prices to just work twice as hard for the same money,(that would be silly) and don't increase prices to reduce sales to all but the most special of moments for "Must have forever" purchases.(again - a bit daft)
Find a good price point, with a bit of life balance and throw in a reasonable living to be made from it if you do a fair days work, and there you go.
What you can do is a reasonable amount of above the line and below the line marketing to emphasise how important a moment that was, and also how valuable they are. And that might just get them to buy it, instead of stealing it. because "they're worth it" as the shampoo advert goes...
There is a reason that parents buy more pictures of their kids than people do of themselves. Parents value their kids and know how special the moment is ! (plus - just think of the costs they have sunk into the whole enterprise!)