It is unfortunate that bumping someone else's request is punishable...
If there existed an old request for let's say a rare book and I wanted the same book it would be of legitimate concern to bump the old post and also let people know that now there are two persons that want the same thing
However it is most probable that this would be abused and the amount of cases arising from this would create a problematic situation for admins and mods... imagine having to deal with hundreds of cases of legitimate bumps mixed with bumps from people with multiple accounts...
So the rules have a reason to be what they are...
And to be quite frank I do not see how bumping is helpful at all...because bumping is without lasting result !
You may bump but if others do it as well and there are new requests on top of that then you will be out of the new picture in no time...
So what users REALLY need is a more permanent measure of urgency and anticipation like a favor system... I have no idea about the limitations of the system this webspace is based upon but if it was possible it would be much more useful than bumping...