The code at Ticketmaster is not a 'smart contract' - I mean it's reasonable to use that as an example to clarify the similarity between TM and 'defi contracts' - however, it truly is 'just code'. There's nothing 'contractual' about it. The 'contracts' and legal implications are signed when you accept terms (a 'contract' between you and TM), and the transfer of money for tickets is regulated by the prevailing regulatory conventions.
I think NFT's may eventually become a form of 'ownership by convention' in which case maybe we could apply a general legal principle (i.e. obtaining and NFT is tantamount to accepting some legal terms). But we'll have to see.
There's literally nothing contractual in "smart contracts". They enforce nothing. It's just code.
Ticketmaster's tickets are actually more of a contract because the ticket you get is actually covered by laws, Ticketmaster provides certain guarantees etc.
I think NFT's may eventually become a form of 'ownership by convention' in which case maybe we could apply a general legal principle (i.e. obtaining and NFT is tantamount to accepting some legal terms). But we'll have to see.