If you undertake general solicitation, you cannot rely on Rule 506(b) to give you an exemption from registration. It does not matter if a sale results from the general solicitation; all that matters is an offer was made by general solicitation. If you lose your exemption, you now find yourself selling unregistered securities – which is something you do not want to be doing.
This is bad news for someone raising capital. Best case is that you have to stop fundraising – and if you need to raise money, that could spell the end of your business.
And the worst case is a lot worse. There are plenty of examples of enforcement actions by the SEC and FINRA against people selling unregistered securities. As one well-known example, in 2017 the SEC published this opinion (pdf will download) which confirmed a disciplinary proceeding that FINRA held against an issuer of securities – and upheld a fine of $73,000 that the issuer had to pay.
In another example (pdf will download), a crypto investment fund being formed had raised over $600k from 22 investors, supposedly under a 506(b) offering. However, it had obviously been generally soliciting investment – publishing information about the new fund on its website, among other things. The fund had to be unwound, the work cancelled, and the principals had to pay a $50,000 fine even though ultimately investors received their capital back.
The SEC can charge larger fines, suspend management teams, strip brokers of their licenses, and impose other punishments if they find the Securities Act or related rules are being violated. Not to mention all the energy dedicated to responding to their requests, the negative press, and the enduring infamy of being in an SEC opinion letter or listed on their litigation page.