That depends on who you ask. Additionally, that is one of the issues that we've constantly brought up. People can reserve seats and it can impact through seating. It also says nothing about the people that miss their trains, reschedule their trips or cancel. To that end:
Yes, you can ask the conductor or call the 1-800 and ask them what seats are opened.
I recognize that this is, in theory, a solution. I say "in theory" because I couldn't do
anything online with this reservation (which, as it turns out, the phone agent botched and I burned a second upgrade card to get into Business on the Regional...mainly because the card is expiring in under two weeks...) and the telephone wait times were pretty bad this weekend (I think I was waiting 7-8 minutes on the Select Executive line on Saturday). Having to burn 10-15 minutes (15 is probably the high end) to have an agent fiddle around with load checks and play a guessing game is no fun; also, when I
did call in, I was simply told "Nope, sold out" when I asked (I didn't know the agents even
could check where seats open up).
When I refer to a "botched implementation", basically the issues are that on the customer's end:
(1) There is no way to check loads before booking, only after, if using the website.
(2) When checking loads/seating availability, there is no way to check the in/out pattern of your seatmate(s) and/or where the neighboring seat(s) are occupied from/to.
Yes, this can be done on a phone call, but...honestly, I feel kinda bad if I'm spending half an hour with an agent trying to pick out a seat, and that's a suck on my time as well as theirs.
Honestly, if it wasn't for the added refundability/flexibility I'd ditch Regional BC at this point. The experience has just become aggravating ("I might get a seatmate in an otherwise empty car because the computer hates me or the algorithm is borked" is just plain obnoxious to think about).