All depends on how you work and whether you can take on the numbers of clients to make up for lower rates.
Many ladies offer discount either just before, or just after Christmas. Doesn't work for me - it's only ever gotten me a few extra bookings, and because I have a limit to the number of clients I wish or need to see each week it didn't mean I saw any extra income, if anything I had to see more clients to make the same money. Another reason would be to attract new clients which might then bring repeat business, but I found this was really very minimal - majority of new enquiries were ummhing, ahhing, mucked about chopping and changing, then couldn't make it after I'd turned down other full rate bookings.
I wouldn't say lowering rates attracts 'undesirables' as such, but it gives a foot in for discussion with those who have been thinking about it for a long time and then will continue to think about it - which includes the 'is there something wrong I'm worried I won't get a proper service' type discussion. Very much in the same way new photos brings emails from those who have been considering a visit for a year or two, just to say how nice you look then spend another year thinking about it.
What I say is give it a go if it works great, if it doesn't then re-evaluate.