yeah i would get them done. after you start to feel more comfortable under the hood with this car you will be able to check them yourself. it's really easy since the plugs are right on the top of the motor.
you can have that ford tech change them. it's really nothing against him or his work that he is not aware of the reason why the plugs blow out. ford is not giving much out for info on this problem. over the years there has been a tsb/ssm recommending the head be replaced if the plug does blow out. then one to re thread it using a special kit. never have they stated the cause of the problem.
once back in the 2002 model year svt dealers got a message telling us to recheck the torque on the plugs (and also do something that i will not even mention because of the controversy it started on here a long time ago, and it's a terrible idea anyways) before delivery of all new lightings ( 5.4 had even more of a problem with the plugs)
ford has been very very tight lipped on this problem. never once has the cause of this problem been mentioned in tsb/ssm's only what to do after it happens.