PF route-to syntax

[Bill Meigs]

I discovered that rules like
pass in on $int_if route-to ($ext_if2 $ext_gw2) from any to any
must route-to an interface and not that interface's ip address. The rule 
set will load without an error message but the route-to rule will not 
work if the ip address is specified.

My first question is am I correct in this understanding. And if I am, 
shouldn't the ruleset fail to load if the route-to rule is not given and 
interface name?

Thanks.