Playing it safe
The problem with this philosophy is that it is not playing it safe at all. In fact, we are playing dangerously close to the edge of the precipice when we refuse to receive a brother for whom Christ died because of disputes over doubtful doctrines and shades of opinion. I don't know how we can consider it "safe" to maintain prejudice against brethren who send their kids to a Christian college, an issue that can only be decided by extrapolated deductions, all while we're in absolute violation of instructions to be longsuffering with our brethren and not to resolve the body of Christ into factions. The extrapolated deductions may even be correct. The factionalism definitely is not.
If a brother truly feels it is safer not to support or endorse a Christian college in any way, then by all means he should not do so. We just need to understand that engaging in the mutual edification of our brethren does not equate to the endorsement of errors we may perceive on their part. Each person needs to take the safest route that his own conscience dictates without forcing others to take the same route. It is not "safe" to force my conscience on others.
I can practice my faith in the utmost safety without fear that singing, praying, or studying with a brother who is in error on some point will somehow lead to my exclusion from the Kingdom. It won't. His conscience is his own, and just as I am not in subjection to his, I cannot place him in subjection to mine. We can certainly submit and defer to each other in love. We can also share our opinions and hope to persuade each other, but at the end of the day, we should continue praising God together with one heart, one mind, and one voice.
Embracing our brother who may be in error on some point is not the same as embracing his error. If it is, we can embrace no brother whatsoever, because we are all in error on some things. It is not compromise to receive him as a brother, because we can remain just as firm in our opinions as we always have. But if he is truly our brother, we have an obligation to receive him in love, to edify him, and to be edified by him. That is the only way to play it safe if we don't want to risk slivering the body of Christ into warring factions.