why "block quick on wlan0" doesn't stop DHCP?

[Michael]

Hello,

Here is my simple rule set:

set loginterface wlan0
block log
block quick on wlan0

Now I'm booting my 8.1-R box. After it's up and running with pf I'm 
powering on my wireless access point.

After couple seconds my wlan0 is associated and receives it's IP 
address. I don't understand why was it not stopped by pf?
And how can I tune my rules to be able to control DHCP conversation?

Michael