No, but it's brittle. A workaround, not a solution. Likely to break
during future maintenance. "Unpredictable" as Mark put it.
Nothing a routing daemon does should involve the kernel BPF. The next
sysadmin won't be expecting it.
Not sure I agree.
Implemented defaults may not be appropriate in all environments and situations, so mechanisms are provided for admins to tune and adjust for what they need. We do this all the time on everything. I'm not ignorant of the fact that this can lend to 'oops' scenarios where someone didn't document the adjustment from default, or it was forgotten, lost, etc. But that's not a technical issue, that's a human one.
There's always a tradeoff to be made. Sysadmins could adjust tunables, but then they have to manage that delta. Or developers can add code to work around the situation, but they have to manage that. Someone has to do work somewhere.