They can add fake tickets to the pool, but the more tickets they add to the pool, the bigger the prize pool will become.
Let's say there are 10 million real tickets and they add 10 million fake tickets to the pool. The lottery is done and there are 5 real winners and 5 fake winners. Now, they pay to 5 people instead of 10, but those 5 winners are paid twice their real prize due to bigger prize pool.
No, it doesn't work that way. They don't raffle off the number of tickets, but when raffling off, they indicate the User ID and their % of winnings. For example, 100 tickets participated in the raffle. User-1 had 99 tickets, and User-2 had only 1 ticket. Accordingly, the ratio is 99% to 1%. The number of tickets doesn't change, but User-1 is manually assigned a value of 0.1% before the raffle, and User-2 is assigned 99.9%, and the number of tickets available, drawn, does not affect at all.
Any casino will always be in profit and they will find a way to deceive you. There is never honesty in a casino. They can write a post from a fake account once a year, like a real person won, like it was 3-4 years ago and that's it. This fake user disappears after the post, and no one else wins anything, but there is intrigue and real users make a deposit against this background.