Have you ever seen what happens when silicone is used to seal a windshield? Because I certainly have, that as well as silicone sealant at the bottom of door frames on an old VW I owned had caused enough rust to seriously impact the ability to restore the car, and lead to me selling it to someone who wanted to build a dune buggy. There are alternative sealants that arent corrosive.
Whether you like my advice or not, I am well within my rights to offer it. You may not agree, thats great, but someone else might find the information useful.
As far as "all the facts" - I'm sorry, I'm not a chemist, but here's a little research.
http://forum.w116.org/auto-torque/silicone-sealants-and-rust/
http://www.jeepsunlimited.com/forums/showthread.php?141742-RTV-sealant-can-cause-rust
https://en.wikipedia.org/wiki/RTV_silicone "Certain types of RTV release acetic acid during the curing process, and this can attack solder joints, causing the solder to detach from the copper wire."
And
I would remove a windshield to fix rust under it. I'm dreading that job on my W123 and hoping I don't have any major rust.