The WTS has been known to take out loans from non-jw banks etc using their property as collateral.
Since the WTS seems to be dunning their members for money despite the sale of some of their properties, I wonder if jws are actually heeding the calls for more donations. Since it is voluntary and somewhat confidential, how do they know who isn't donating? I doubt that tithing is an option unless they backdoor it like expecting congregation donations to be the same as their forgiven mortgage payment, oh they do that already. But then it is only at the congregation level not by individuals.