There's one other reason to turn in your logs, if you can:
The automated (computer) score checking systems employed by the contest committees who have the right to alter entrants' scores, or even disqualify entrants, look for UNIQUE calls. A unique call is one found in one contester's log but not found in any other logs.
Years ago, this was difficult to check for, since everything was manual. Now that the logs are submitted electronically, they're checked that way, too. It only takes a second for the program to spit out UNIQUES, and if one entrant has too many UNIQUES, his score can be reduced -- and he can even be disqualified -- because it is unbelievable that one station would work so many UNIQUE calls not found in others' logs.
So, it is "kind" to all those you contacted if you send in your log!
Unfortunately, ARRL, CQ, et al no longer accept "paper" logs at all, and any log submitted must be via electronic means in Cabrillo format. That format is exported by all popular logging software, but if you're not using any (and just a paper and pencil), you can't submit a log, even if you want to.
WB2WIK/6