dpkg (without any --force) allows to break dependences

["Nikita V. Youshchenko" <yoush@cs.msu.su>]

How to reproduse:

create test1_1.deb with package 'test1', version '1'
creaet test1_2.deb with package 'test1', version '2'
create test2.deb with package 'test2' that depends on test1 (>= 2)

dpkg -i test1_2.deb
dpkg -i test2.deb
dpkg -i test1_1.deb

The last commands completes without errors, and breaks dependency for
installed and configured package test2.
Package test2 is still "install ok installed".

This happens with dpkg 1.10.10 on a sid system.

Do I misunderstand something, or this is a serious bug in dpkg?