We cannot be sure of how that user got them but look at their ID,it is with 5 digit and it means it is from the early early days,I am with 6 digits and consider myself of somewhat early user but this one is from the first ones.Based on this I can clearly say that this guy to have lots of referrals as these users are the ones who started to spread the word at that time and as such he got a lot of refs most likely.The refs maybe were gamblers and maybe he is a gambler himself so that is the most likely explanation for getting that huge amount of tickets.
We can easily check this because Freebitcoin periodically posts screenshots of daily jackpot leaderboards in this thread. Just take a look at this
post. This whale wagered over 100 BTC in just 1 day last week. Therefore, there is no doubt he collects such a large number of lottery tickets either through betting on events or wagering in the hi/lo game rather than through referrals.