You do know that neither merchants nor folks writing tax or sales software can "get rid of sales taxes", right?
"Our software doesn't handle that case" isn't a defense against a tax evasion charge.
Neither is "I forgot" or "Excuse me", despite what Steve Martin said.
https://snltranscripts.jt.org/77/77imono.phtml
You.. can be a millionaire.. and never pay taxes! You can be a millionaire.. and never pay taxes! You say.. “Steve.. how can I be a millionaire.. and never pay taxes?” First.. get a million dollars. Now.. you say, “Steve.. what do I say to the tax man when he comes to my door and says, ‘You.. have never paid taxes’?” Two simple words. Two simple words in the English language: “I forgot!” How many times do we let ourselves get into terrible situations because we don’t say “I forgot”? Let’s say you’re on trial for armed robbery. You say to the judge, “I forgot armed robbery was illegal.” Let’s suppose he says back to you, “You have committed a foul crime. you have stolen hundreds and thousands of dollars from people at random, and you say, ‘I forgot’?” Two simple words: Excuuuuuse me!!“