My experience as a member was that you could always get a ticket if acted reasonably quickly. Obviously best seats belong to the ST holders, so limited in centre Kingsland unless you want to sit at back. No problem either end of Kingsland. I suspect that the more members there are, the harder for ST holders to get an extra ticket, but would be surprised if it became impossible as I doubt members would take up all spare tickets.
Depends how many we sell - this year we sold the maximum amount of ST's allowed. I do think though that was mainly because we were in Europe and people didn't want to miss out, as it happens it didn't matter too much but will be interesting to see how many we sell this year if not in EL.
Always some who have to let go of STs for one reason or another, but I bet we have as many ST holders next season...it has been enjoyable and I think most will be hopeful that next season will be a good 'un.
On another note the 18-21 bracket is very, very good value, good work there Saints. I remember the old 'young adult' tickets when in L1 (and I was eligible) Good way of getting fans in.