I believe that they don't want to prevent people from lending higher amounts, but that they just want to convey the message that massive lending is not welcome. Even if the possibility to change the amount in the second step were removed, there would be another way to cheat: make many loans of $25 to the same person. The small loans add up and there is only one record in the database.
Robert,
you can't have it both ways: limit and not limit.
I think that KIVA wants to limit, because as Steve confirmed in another thread
http://www.kivafriends.org/index.php/topic,974.msg9114.html#msg9114 there is a one loan per day limit.
Henry, yes you are right. At least us KIVAN's who are aware of the situation should behave and limit ourselves to $25 per loan, but it is also KIVA's responsibility to close the loop holes.
Ulli