I didn't even know you could drop a name within 5 days? How do you do that..
Registrars like Dynadot for one allow you to "cancel" any registrations within a 4-5 day period for a cost of .20. They show you the time remaining on your Account Summary.
There are many that use this "cancellation window" for legitimate purposes, particulary those that register IDNs- International Domain Names using online translators and dictionaries. Many times it is helpful to register the name pending further confirmation of the proper translation, best term etc. by native speakers.
Too many times you can check availablity of a name, and then come back a day later and find it registered. The ability to register IDN names that you are relatively confident in, and have time to get forum "appraisals" from members that speak the various languages is a good benefit.
I am against bulk "tasting", or think the fee for that should be .50 and used to help hold down overall cost of registration fees and renewals.