Hm... so if i will get into siege server with 20 clanmates to build catapult in about 20 secs (then we die and come back with full equipement, few men to use catapult, too), will you destroy it? Yeah, dont let your teammate actually REMOVE defenders gate. No more closing opening, because gate will disappear! Did you ever see how works catapult? Organized group (about 15 people), each member with 4 materials and 1 with constr site can really build something nice in 10-20 secs.
How do you respawn on battle server? ...
However, as long as the guys dont spawn with only 4 construction thingys, but with at least 1 weapon, it would seem ok for me, as long as they dont need 3 minutes to build it up while half there team get raped .... so either do it organised so that it doesnt take long or convice your team to help you or to camp while your are building your thingys ...