You have to pull out cash from the bank for a bank run to occur. Can't you buy gold or some other cash substitute instead?
Could be even more difficult to detect than abnormal spike in cash withdrawals via ATMs.
Spending money is taking money out of your bank account. Any event where more money leaves a bank than they have reserves to cover it is a run on the bank. I think what you may be elluding to is that digital transfer of funds makes the effects of a bank run different than than when cash is involved, since real money in hand cash is much more limited than a bank’s total reserves.