I am an artist in the Northwest Suburbs of Chicago w/ this exact resonating concern. To the degree that my trunk WAS broken into on New Years Eve / Day in Detroit. Yes, I dropped the ball.
State Farm made that whole experience a little less miserable, save for the fact that the car audio company they go through (AJRS) are clown shoes when it comes to explaining your remaining credit voucher to you. Be prepared for teenagers to up-sell you equipment you do not need, such as $115 for three pairs of Interconnects, & then charge you a 20% restocking fee when you don't want them.
But I digress.
Anyone who can install toggle switches in their dash to kill amplifiers can certainly relocate that trunk button elsewhere in the vehicle, or perhaps integrate a series of toggle switches accompanied by an arcade button. Something to defeat the obvious route to get that door open & press the trunk LOGO-ed button in plain view.
Bypassing the trunk button will also allow for additional, more flexible options such as wiring a $5 Hallmark card that records a message (perhaps 'F--k you, sir') for each time that trunk button is pressed. None of this is hard to do, people that race Import Tuners install dummy switches into their cars that over-ride the ignition switch to prevent hot-wiring, etc.
There's definitely some room to think outside the box w/ a Mercury Milan, since as was mentioned in the original post, there is no valet key or trunk lock.
This may not be an answer but it's what I am now doing this weekend.
The prking break is probably on...
Best places are the local auto store. Depending on where you live it will be called something different. Auto Zone, Advanced Auto, NAPA, Checkers, Are just a few. They serve the do it yourselfer very well and can provide a multitude of tools as well. Many have several options on the parts as well. From a 3 month warranty to a lifetime warranty. The best ones will take your information and place in their computer so if you loose the receipt, or the sun removes the writing, you can still return the part for replacement. Most brake repair shops do not supply parts to the do it yourself er. JOnathon
1) Check this site: http://www.mtphistory.org/new_page_22.htm "Camp Pine - On the northwest boarder of what is today Mount Prospect is a Cook County forest preserve. On the eastern side of the Des Plaines River (near the intersection of Euclid and River Road) was a WWII German POW camp called Camp Pine. Around 200 German soldiers were held here through the war, living in 5 barracks with a mess tent. Many of them worked outside of the camp at local farms and some worked at Pesche's flowers. After the war, the buildings from this camp were used by girl and boy scout troops. We would like any information, memories, or photos of this camp, either as a POW camp or as a scout camp." 2) Also, http://vikingphoenix.com/guestbook/guestbook.html "I am looking for any information that is available regarding a German POW camp called Camp Pine that was just outside DesPlaines Illinois. It was one of several small camps in the Chicago area where prisoners were used on the farms to offset the man shortage due to the war. Control of these sattelite camps was handled through Fort Sheridan Illinois, a fort that is now dismantled. I have not been able to trace where the historical data kept at the fort museum went when the fort closed. Any information would be greatly appreciated about the fort records or especially Camp Pine. Don Klich Don Klich Desplaines, IL USA - Tuesday, February 17, 2004 at 16:05:18 (EST)" 3) Also, from the Cook Cty Forest Preserves and other sources, see Sweet Woods Forest Preserve, Glenwood, IL - Was a German POW camp during World War II. The prisoners drew a U.S. flag in cement, which still remains there today. Located at N41.5513, W87.61449. Take Interstate 394 South to Glenwood Dyre Rd exit turn right to St. Lawrence Ave. turn right to Glenwood Lansing Rd. then turn left to Cottage Grove st. (north) look for Sweet Woods Forest Preserve entrance on your left. park at the end of prking lot head past stone patio to trail entrance. 4) Also, from what I read Fort Sheridan, Illinois was a facility from which POWs were sent to other places.