We are using ArchitecturesAllowed and it is working fine at present.
Is it possible to use something like a command line parameter to instruct Inno to "ignore ArchitecturesAllowed, just install it anyway"?
I don't see anything like this in https://jrsoftware.org/ishelp/index.php?topic=setupcmdline. I know its possible to create custom command line params but I don't see how programmatically that would allow for this.
This might be useful for us in some strange corner cases where our installer does not support a particular architecture but we need to work around a customer problem. (Specifically I'm thinking of Windows 11 running in a VM on a Mac, but there could be other cases.)
I know there are approaches like in Can Inno Setup detect Windows11 on ARM64 hardware which can emulate x64? which allow circumventing ArchitecturesAllowed entirely, but that seems like an alternative approach.
Also I can see that the error message can be customized; but that doesn't change the actual setup behavior: Show a custom message for unsupported architectures
No.
Using the approach you know (Can Inno Setup detect Windows11 on ARM64 hardware which can emulate x64?) combined with a custom command line switch is the only way.