Would playdate be able to sue FedEx or take them to small claims court or do you sign something when you use FedEx that says you can't sue them for XYZ?
'you cannot sue us for not doing the only thing you are paying us for (delivering your goods)' sounds like an inconscionable clause. Surely any worthwhile legal system would make such clauses illegal. Otherwise many scams (fake invoicing, for example) would be essentially legal as long the perp buried a clause in a contract.