I use United all the time and it has never been a problem checking my bag all the way thru to MDC that being said I haven't used Continental I usually use Singapore Air between United and Silk Air so that may be a hiccup but I'm willing to bet it can be done. As for boarding passes when you arrive in Terminal 3 go to the Singapore Air counter(inside terminal 3) and talk with them about getting boarding passes for you Silk Air flight. If it is within 24 hours and it is in your case they can issue you a boarding pass. They issued me a boarding pass for my United flight from LAX to DEN on United when I returned from MDC over xmas. I was able to check my bag in Manado all the way to Denver even though Silk couldn't issue me a boarding pass on United since my flight was over 24 hours away when I left Manado. I did have to pick up my bag in LAX and clear customs but then I was able to just hand it over in the international terminal and they rechecked it and sent to correct terminal.
Don't know if you are going to Bunaken or Lembeh but Lembeh is worth it. Been to Lembeh 4 times and it is my favorite spot on the planet. Bunaken ain't bad either but Lembeh is AWESOME.
Just reread your post and you said you are traveling on Singapore Air as a partner. So United will definitely let you check all the way to MDC. Don't sweat it just bring your itinerary and it will definitely be in the computer system as well.
Don't know if you are going to Bunaken or Lembeh but Lembeh is worth it. Been to Lembeh 4 times and it is my favorite spot on the planet. Bunaken ain't bad either but Lembeh is AWESOME.
Just reread your post and you said you are traveling on Singapore Air as a partner. So United will definitely let you check all the way to MDC. Don't sweat it just bring your itinerary and it will definitely be in the computer system as well.