[sgman]

Look at the bottom of your checks. You give out your account number (and routing number) every time you issue a check.

[dpark]

I avoid writing checks as much as possible in part because of that.

Knuth stopped sending checks for rewards specifically because it turns out that giving random people your account info is a bad idea.

[yxhuvud]

The only thing an account number gives access to is sending cash to it.

I fail to see what negative consequences that have.